object type - Page 413 - Developer IT

PHP class extends not working why and is this how to correctly extend a class?

- by Matthew

Hi so I'm trying to understand how inherteince works in PHP using object oriented programming. The main class is Computer, the class that is inheriting is Mouse. I'm extedning the Computer class with the mouse class. I use __construct in each class, when I istinate the class I use the pc type first and if it has mouse after. For some reason computer returns null? why is this? class Computer { protected $type = 'null'; public function __construct($type) { $this->type = $type; } public function computertype() { $this->type = strtoupper($this->type); return $this->type; } } class Mouse extends Computer { protected $hasmouse = 'null'; public function __construct($hasmouse){ $this->hasmouse = $hasmouse; } public function computermouse() { if($this->hasmouse == 'Y') { return 'This Computer has a mouse'; } } } $pc = new Computer('PC', 'Y'); echo $pc->computertype; echo $pc->computermouse;

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PHP - Pull out array keys that have matching values?

- by MAZUMA

Is there a way to look inside an array and pull out the keys that have keys with matching values? Questions like this have been asked, but I'm not finding anything conclusive. So if my array looks like this Array ( [0] => Array ( [title] => Title 1 [type] => [message] => ) [1] => Array ( [title] => Title 2 [type] => [message] => ) [2] => Array ( [title] => Title 3 [type] => [message] => ) [3] => Array ( [title] => Title 2 [type] => Limited [message] => 39 ) [4] => Array ( [title] => Title 4 [type] => Offline [message] => 41 ) [5] => Array ( [title] => Title 5 [type] => [message] => ) And I want to get this Array ( [1] => Array ( [title] => Title 2 [type] => [message] => ) [3] => Array ( [title] => Title 2 [type] => Limited [message] => 39 ) )

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QoS basics on a Cisco ASA

- by qbn

Could someone briefly explain how to use QoS on Cisco ASA 5505? I have the basics of policing down, but what about shaping and priorities? Basically what I'm trying to do is carve out some bandwidth for my VPN subnets (in an object-group called priority-traffic). I've seen this Cisco QoS document, however configuring shaping and priority-queue don't seem to have any effects in my test. A full download of the linux kernel from kernel.org will boost a ping to a server via VPN sky high. Policing has been successful in passing this test, although it doesn't seem as efficient (I cap non-vpn traffic at 3 of my 4.5 megabits of bandwidth). Am I misunderstanding the results of the test? I think there is some simple concept I'm not grasping here. EDIT: Here is my config thus far (I have 4.5 megabits of bandwidth): access-list priority-traffic extended permit ip object-group priority-traffic any access-list priority-traffic extended permit ip any object-group priority-traffic access-list priority-traffic extended permit icmp object-group priority-traffic any access-list priority-traffic extended permit icmp any object-group priority-traffic access-list non-priority-traffic extended deny ip object-group priority-traffic any access-list non-priority-traffic extended deny ip any object-group priority-traffic access-list non-priority-traffic extended permit ip any any priority-queue outside queue-limit 440 class-map non-priority-traffic match access-list non-priority-traffic class-map priority-traffic match access-list priority-traffic class-map inspection_default match default-inspection-traffic policy-map type inspect dns preset_dns_map parameters message-length maximum 512 policy-map global_policy class inspection_default inspect dns preset_dns_map inspect ftp inspect h323 h225 inspect h323 ras inspect rsh inspect rtsp inspect sqlnet inspect skinny inspect sunrpc inspect xdmcp inspect sip inspect netbios inspect tftp policy-map outbound-qos-policy class non-priority-traffic police input 2500000 police output 2500000 class priority-traffic priority service-policy global_policy global service-policy outbound-qos-policy interface outside

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Postfix won't run while selinux in enforcing mode

- by Dina Abu-khader

I enabled selinux forcing mode on Fedora 15 , and I was able to get apache, mysql and memcached to work fine , but I couldn't get postfix to run . I got the following errors : systemd[1]: Unit postfix.service entered failed state. kernel: [146194.117602] type=1400 audit(1318924444.361:3809): avc: denied { module_request } for pid=15447 comm="postfix" kmod="net-pf-10" scontext=system_u:system_r:postfix_master_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system kernel: [146194.145456] type=1400 audit(1318924444.389:3810): avc: denied { module_request } for pid=15452 comm="master" kmod="net-pf-10" scontext=system_u:system_r:postfix_master_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system kernel: [146194.146585] type=1400 audit(1318924444.390:3811): avc: denied { module_request } for pid=15452 comm="master" kmod="net-pf-10" scontext=system_u:system_r:postfix_master_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system kernel: [146194.390715] type=1400 audit(1318924444.633:3812): avc: denied { module_request } for pid=15479 comm="postsuper" kmod="net-pf-10" scontext=system_u:system_r:postfix_master_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system kernel: [146194.451670] type=1400 audit(1318924444.694:3813): avc: denied { module_request } for pid=15516 comm="postlog" kmod="net-pf-10" scontext=system_u:system_r:postfix_master_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system kernel: [146194.459587] type=1400 audit(1318924444.702:3814): avc: denied { module_request } for pid=15517 comm="master" kmod="net-pf-10" scontext=system_u:system_r:postfix_master_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system kernel: [146194.460786] type=1400 audit(1318924444.703:3815): avc: denied { module_request } for pid=15517 comm="master" kmod="net-pf-10" scontext=system_u:system_r:postfix_master_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system systemd[1]: PID 15517 read from file /var/spool/postfix/pid/master.pid does not exist. Your service or init script might be broken. systemd[1]: postfix.service: main process exited, code=exited, status=1 following steps were done : I reinstall postfix Created .autorelable and reboot restorecon -R -v /etc/postfix restorecon -R -v /var/lib/postfix Can someone tell me what am doing wrong ? Update It turns out that we have to disable the ipv6 in the main.cf and these errors were disappear. THank you

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CoreStore Encryption Error on Mac Lion

- by Michael

I am trying to encrypt an external drive using diskutil CoreStorage on Mac Lion 10.7.4. I thought the only requirements were that the drive have GUID partition scheme and Journaled HFS+ file system. I think my drive is configured accordingly but when I type the following command I get an error message back: Michaels-MacBook-Pro:~ Michael$ diskutil cs convert disk2 -passphrase TestPassword Error converting disk to CoreStorage: The given file system is not supported on Core Storage (-69756) Here are the details reported for the drive in question: Michaels-MacBook-Pro:~ Michael$ diskutil list disk2 /dev/disk2 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.1 GB disk2 1: EFI 209.7 MB disk2s1 2: Apple_HFS Test1 499.8 GB disk2s2 Michaels-MacBook-Pro:~ Michael$ diskutil list disk2 /dev/disk2 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.1 GB disk2 1: EFI 209.7 MB disk2s1 2: Apple_HFS Test1 499.8 GB disk2s2 Michaels-MacBook-Pro:~ Michael$ diskutil info disk2s2 Device Identifier: disk2s2 Device Node: /dev/disk2s2 Part of Whole: disk2 Device / Media Name: Test1 Volume Name: Test1 Escaped with Unicode: Test1 Mounted: Yes Mount Point: /Volumes/Test1 Escaped with Unicode: /Volumes/Test1 File System Personality: Journaled HFS+ Type (Bundle): hfs Name (User Visible): Mac OS Extended (Journaled) Journal: Journal size 40960 KB at offset 0xe8e000 Owners: Disabled Partition Type: Apple_HFS OS Can Be Installed: Yes Media Type: Generic Protocol: FireWire SMART Status: Not Supported Volume UUID: 1024D0B8-1C45-3057-B040-AE5C3841DABF Total Size: 499.8 GB (499763888128 Bytes) (exactly 976101344 512-Byte-Blocks) Volume Free Space: 499.3 GB (499315826688 Bytes) (exactly 975226224 512-Byte-Blocks) Device Block Size: 512 Bytes Read-Only Media: No Read-Only Volume: No Ejectable: Yes Whole: No Internal: No I'm a little concerned that the "Partition Type: Apple_HFS" entry is causing the problem, but I don't know how to change that. I only seem to be able to control the "File System Personality: Journaled HFS+" in Disk Utility. Can anyone shed some light on this for me?

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Disabling CPU management

- by Tiffany Walker

If I add the following processor.max_cstate=0 to the kernel command line for boot up, does that disable all CPU power management and throttling? I also found: http://www.experts-exchange.com/OS/Linux/Administration/A_3492-Avoiding-CPU-speed-scaling-in-modern-Linux-distributions-Running-CPU-at-full-speed-Tips.html The link talks of Change CPU governor from 'ondemand' to 'performance' for all CPUs/cores and disabling kondemand from kernel. Server is for web hosting UPDATES: 2.6.32-379.1.1.lve1.1.7.6.el6.x86_64 #1 SMP Sat Aug 4 09:56:37 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux . # dmidecode 2.11 SMBIOS 2.6 present. 74 structures occupying 2878 bytes. Table at 0x0009F000. Handle 0x0000, DMI type 0, 24 bytes BIOS Information Vendor: American Megatrends Inc. Version: 1.0c Release Date: 05/27/2010 Address: 0xF0000 Runtime Size: 64 kB ROM Size: 4096 kB Characteristics: ISA is supported PCI is supported PNP is supported BIOS is upgradeable BIOS shadowing is allowed ESCD support is available Boot from CD is supported Selectable boot is supported BIOS ROM is socketed EDD is supported 5.25"/1.2 MB floppy services are supported (int 13h) 3.5"/720 kB floppy services are supported (int 13h) 3.5"/2.88 MB floppy services are supported (int 13h) Print screen service is supported (int 5h) 8042 keyboard services are supported (int 9h) Serial services are supported (int 14h) Printer services are supported (int 17h) CGA/mono video services are supported (int 10h) ACPI is supported USB legacy is supported LS-120 boot is supported ATAPI Zip drive boot is supported BIOS boot specification is supported Targeted content distribution is supported BIOS Revision: 8.16 Handle 0x0001, DMI type 1, 27 bytes System Information Manufacturer: Supermicro Product Name: X8SIE Version: 0123456789 Serial Number: 0123456789 UUID: 49434D53-0200-9033-2500-33902500D52C Wake-up Type: Power Switch SKU Number: To Be Filled By O.E.M. Family: To Be Filled By O.E.M. Handle 0x0002, DMI type 2, 15 bytes Base Board Information Manufacturer: Supermicro Product Name: X8SIE Version: 0123456789 Serial Number: VM11S61561 Asset Tag: To Be Filled By O.E.M. Features: Board is a hosting board Board is replaceable Location In Chassis: To Be Filled By O.E.M. Chassis Handle: 0x0003 Type: Motherboard Contained Object Handles: 0 Handle 0x0003, DMI type 3, 21 bytes Chassis Information Manufacturer: Supermicro Type: Sealed-case PC Lock: Not Present Version: 0123456789 Serial Number: 0123456789 Asset Tag: To Be Filled By O.E.M. Boot-up State: Safe Power Supply State: Safe Thermal State: Safe Security Status: None OEM Information: 0x00000000 Height: Unspecified Number Of Power Cords: 1 Contained Elements: 0

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Editing a windows XP installation's registry without being able to log in.

- by Alain

I've got a windows XP installation that has a corrupt registry. A worm (which was removed) had hijacked the HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon entry (which should have a value of Userinit=C:\windows\system32\userinit.exe When the worm was removed, the corrupt entry was deleted entirely, and now the system automatically logs off immediately after attempting to log in. Regardless of the user and boot mode, no accounts can be logged in to. The only thing required to correct this behavior is to restore the registry key, but I cannot come up with any ways of editing the registry without logging in to an account. I tried remotely connecting to the registry but the required services aren't enabled on the machine. I tried booting on the same machine using the BartPE boot CD but I could not find any way of editing the registry on the C:\Windows installation - running regedit only modifies the X:\I386\ registry in memory. So, what can I use modify the registry of an un-login-able Windows XP instance so that I can log in again? Thanks guys. EDIT: The fix worked. The solution to the auto-logoff problem was, as hoped, to simply add the value mentioned above to the appropriate registry entry. This can be done using the BartPE Boot CD, as described in the accepted answer below, but I used the Offline NT Registry Editor software mentioned in another answer. The steps were: Boot from the NT Registry Editor CD Follow the directions until the appropriate boot sector is loaded. Instead of using one of the default options for modifying passwords or user accounts, type "software" to edit that hive. Type '9' to enter the command line based registry editor. Type "cd Microsoft" (enter) "cd Windows NT" (enter) "cd CurrentVersion" (enter) "cd Winlogon" (enter) Type "nv 1 Userinit" to create a new value under the Winlogon key Type "ev Userinit" to edit the new value, and when prompted, type "C:\windows\system32\userinit.exe" (enter) Type 'q' to quit the registry editor, and as you back out of the system, follow directions to write the hive back to disk. Restart your computer and log in - problem solved. (generic 'warning: back up your registry' disclaimer)

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Ubuntu: Getting rid of a mimetype entry

- by Epaga

I have a pesky mimetype entry that I can't seem to get rid of. Here is the current situation: xdg-mime query filetype myfile.mfe application/pesky Using assogiate I have found out the information about this mime type entry (but can't delete it there). I have the following 'pesky.xml' XML file which was used to create the mime type (as far as I can tell, since it exactly matches the entry in assogiate...): <?xml version='1.0'?> <mime-info xmlns='http://www.freedesktop.org/standard'> <mime-type type="application/pesky"> <comment>my pesky type</comment> <glob pattern="*.mfe"/> <magic priority="100"> <match type="string" offset="0" value="application/pesky"/> </magic> </mime-type> <mime-info> However, the following has no effect: sudo xdg-mime uninstall --mode system --novendor pesky.xml The file association remains. Any ideas?

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Can't ssh from CentOS 6.5 to SUSE LINUX 10.1

- by Pavel Tankov

We have a quite old installation of SUSE LINUX 10.1 (i586) in the office. The problem shortly: I can successfully ssh to it from machines in the same LAN (192.168.1.0) and not from others (that are in 10.23.0.0). The SuSE has SSH server openssh-4.2p1-18.12. I have ruled out the firewall and hosts.allow and hosts.deny files. When my ssh login attempt fails, here is what the logs say: on the client: $ ssh -vvv 192.168.1.5 OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to 192.168.1.5 [192.168.1.5] port 22. debug1: Connection established. debug1: identity file /home/nbuild/.ssh/identity type -1 debug1: identity file /home/nbuild/.ssh/identity-cert type -1 debug1: identity file /home/nbuild/.ssh/id_rsa type -1 debug1: identity file /home/nbuild/.ssh/id_rsa-cert type -1 debug1: identity file /home/nbuild/.ssh/id_dsa type -1 debug1: identity file /home/nbuild/.ssh/id_dsa-cert type -1 on the server: Aug 21 16:34:25 serverhost sshd[20736]: debug3: fd 4 is not O_NONBLOCK Aug 21 16:34:25 serverhost sshd[20736]: debug1: Forked child 20739. Aug 21 16:34:25 serverhost sshd[20736]: debug3: send_rexec_state: entering fd = 7 config len 403 Aug 21 16:34:25 serverhost sshd[20736]: debug3: ssh_msg_send: type 0 Aug 21 16:34:25 serverhost sshd[20736]: debug3: send_rexec_state: done Aug 21 16:34:25 serverhost sshd[20739]: debug1: rexec start in 4 out 4 newsock 4 pipe 6 sock 7 Aug 21 16:34:25 serverhost sshd[20739]: debug1: inetd sockets after dupping: 3, 3 Aug 21 16:34:25 serverhost sshd[20739]: debug3: Normalising mapped IPv4 in IPv6 address Aug 21 16:34:25 serverhost sshd[20739]: Connection from 10.23.1.11 port 44340 The above log on the server is when I enable DEBUG3 log level. However, with the default log level (INFO), the only thing the server logs is this: Aug 21 16:38:32 serverhost sshd[20749]: Did not receive identification string from 10.23.1.11 Any hints? I feel I've tried everything already.

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Why is there an extra HDD under /dev being added in my Linux Kernel?

- by user1279156

I have created a Linux kernel and for some reason an extra drive is always added at bootup. My hard drive is listed as /dev/sdb. /dev/sda is created too, and it is 8 MB in size. I can't find anything in the kernel config that is creating this, but if I use a different kernel it is not there. Kernel logs show it as an attached SCSI device, looks just like my hard drive but only 8 MB, and has no partition table. It also doesn't appear to be a physical device. I've tried the kernel on many different models of PCs and it is always there. Does anyone know how to remove it? /dev/disk/by-id gives me: scsi-1AMCC_U21413034D98EB000584 scsi-1AMCC_U21413034D98EB000584-part1 scsi-353333330000007d0 scsi-SATA_ST3250312AS_5VY7SH42 scsi-SATA_WDC_WD800JD-60L_WD-WMAM9Y085675 scsi-SATA_WDC_WD800JD-60L_WD-WMAM9Y085675-part1 scsi-SATA_WDC_WD800JD-60L_WD-WMAM9Y085675-part2 hdparm -i /dev/sda gives me an "invalid argument". dd if=/dev/sda of=sda.img the resulting file does not have any content sdparm results: /dev/sda: Linux scsi_debug 0004 Device identification VPD page: Addressed logical unit: designator type: T10 vendor identification, code set: ASCII vendor id: Linux vendor specific: scsi_debug 2000 designator type: NAA, code set: Binary 0x53333330000007d0 Target port: designator type: Relative target port, code set: Binary transport: Serial Attached SCSI (SAS) Relative target port: 0x1 designator type: NAA, code set: Binary transport: Serial Attached SCSI (SAS) 0x52222220000007ce designator type: Target port group, code set: Binary transport: Serial Attached SCSI (SAS) Target port group: 0x100 Target device that contains addressed lu: designator type: NAA, code set: Binary transport: Serial Attached SCSI (SAS) 0x52222220000007cd designator type: SCSI name string, code set: UTF-8 transport: Serial Attached SCSI (SAS) SCSI name string: naa.52222220000007CD

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Using Unity – Part 2

- by nmarun

In the first part of this series, we created a simple project and learned how to implement IoC pattern using Unity. In this one, I’ll show how you can instantiate other types that implement our IProduct interface. One place where this one would want to use this feature is to create mock types for testing purposes. Alright, let’s dig in. I added another class – Product2.cs to the ProductModel project. 1: public class Product2 : IProduct 2: { 3: public string Name { get; set;} 4: public Category Category { get; set; } 5: public DateTime MfgDate { get;set; } 6: 7: public Product2() 8: { 9: Name = "Canon Digital Rebel XTi"; 10: Category = new Category {Name = "Electronics", SubCategoryName = "Digital Cameras"}; 11: MfgDate = DateTime.Now; 12: } 13: 14: public string WriteProductDetails() 15: { 16: return string.Format("Name: {0}<br/>Category: {1}<br/>Mfg Date: {2}", 17: Name, Category, MfgDate.ToShortDateString()); 18: } 19: } Highlights of this class are that it implements IProduct interface and it has some different properties than the Product class. The Category class looks like below: 1: public class Category 2: { 3: public string Name { get; set; } 4: public string SubCategoryName { get; set; } 5: 6: public override string ToString() 7: { 8: return string.Format("{0} - {1}", Name, SubCategoryName); 9: } 10: } We’ll go to our web.config file to add the configuration information about this new class – Product2 that we created. Let’s first add a typeAlias element. 1: <typeAlias alias="Product2" type="ProductModel.Product2, ProductModel"/> That’s all that is needed for us to get an instance of Product2 in our application. I have a new button added to the .aspx page and the click event of this button is where all the magic happens: 1: private IUnityContainer unityContainer; 2: protected void Page_Load(object sender, EventArgs e) 3: { 4: unityContainer = Application["UnityContainer"] as IUnityContainer; 5: 6: if (unityContainer == null) 7: { 8: productDetailsLabel.Text = "ERROR: Unity Container not populated in Global.asax.<p />"; 9: } 10: else 11: { 12: if (!IsPostBack) 13: { 14: IProduct productInstance = unityContainer.Resolve<IProduct>(); 15: productDetailsLabel.Text = productInstance.WriteProductDetails(); 16: } 17: } 18: } 19: 20: protected void Product2Button_Click(object sender, EventArgs e) 21: { 22: unityContainer.RegisterType<IProduct, Product2>(); 23: IProduct product2Instance = unityContainer.Resolve<IProduct>(); 24: productDetailsLabel.Text = product2Instance.WriteProductDetails(); 25: } The unityContainer instance is set in the Page_Load event. Line 22 in the click event of the Product2Button registers a type mapping in the container. In English, this means that when unityContainer tries to resolve for IProduct, it gets an instance of Product2. Once this code runs, following output is rendered: There’s another way of doing this. You can resolve an instance of the requested type with a name from the container. We’ll have to update the container element of our web.config file to include the following: 1: <container name="unityContainer"> 2: <types> 3: <type type="IProduct" mapTo="Product"/> 4:  5: <type type="IProduct" mapTo="Product" name="LegacyProduct" /> 6:  7: <type type="IProduct" mapTo="Product2" name="NewProduct" /> 8: </types> 9: </container> I’ve added a Dropdownlist and a button to the design page: 1: <asp:DropDownList ID="ModelTypesList" runat="server"> 2: <asp:ListItem Text="Legacy Product" Value="LegacyProduct" /> 3: <asp:ListItem Text="New Product" Value="NewProduct" /> 4: </asp:DropDownList> 5: <br /> 6: <asp:Button ID="SelectedModelButton" Text="Get Selected Instance" runat="server" 7: onclick="SelectedModelButton_Click" /> 1: protected void SelectedModelButton_Click(object sender, EventArgs e) 2: { 3: // get the selected value: LegacyProduct or NewProduct 4: string modelType = ModelTypesList.SelectedValue; 5: // pass the modelType to the Resolve method 6: IProduct customModel = unityContainer.Resolve<IProduct>(modelType); 7: productDetailsLabel.Text = customModel.WriteProductDetails(); 8: } Pretty straight forward right? The only thing to note here is that the values in the dropdownlist item need to match the name attribute of the type. Depending on what you select, you’ll get an instance of either the Product class or the Product2 class and the corresponding WriteProductDetails() method is called. Now you see, how either of these methods can be used to create mock objects your the test project. See the code here. I’ll continue to share more of Unity in the next blog.

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Using delegates in C# (Part 2)

- by rajbk

Part 1 of this post can be read here. We are now about to see the different syntaxes for invoking a delegate and some c# syntactic sugar which allows you to code faster. We have the following console application. 1: public delegate double Operation(double x, double y); 2: 3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: Operation op1 = new Operation(Division); 9: double result = op1.Invoke(10, 5); 10: 11: Console.WriteLine(result); 12: Console.ReadLine(); 13: } 14: 15: static double Division(double x, double y) { 16: return x / y; 17: } 18: } Line 1 defines a delegate type called Operation with input parameters (double x, double y) and a return type of double. On Line 8, we create an instance of this delegate and set the target to be a static method called Division (Line 15) On Line 9, we invoke the delegate (one entry in the invocation list). The program outputs 5 when run. The language provides shortcuts for creating a delegate and invoking it (see line 9 and 11). Line 9 is a syntactical shortcut for creating an instance of the Delegate. The C# compiler will infer on its own what the delegate type is and produces intermediate language that creates a new instance of that delegate. Line 11 uses a a syntactical shortcut for invoking the delegate by removing the Invoke method. The compiler sees the line and generates intermediate language which invokes the delegate. When this code is compiled, the generated IL will look exactly like the IL of the compiled code above. 1: public delegate double Operation(double x, double y); 2: 3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: //shortcut constructor syntax 9: Operation op1 = Division; 10: //shortcut invoke syntax 11: double result = op1(10, 2); 12: 13: Console.WriteLine(result); 14: Console.ReadLine(); 15: } 16: 17: static double Division(double x, double y) { 18: return x / y; 19: } 20: } C# 2.0 introduced Anonymous Methods. Anonymous methods avoid the need to create a separate method that contains the same signature as the delegate type. Instead you write the method body in-line. There is an interesting fact about Anonymous methods and closures which won’t be covered here. Use your favorite search engine ;-)We rewrite our code to use anonymous methods (see line 9): 1: public delegate double Operation(double x, double y); 2: 3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: //Anonymous method 9: Operation op1 = delegate(double x, double y) { 10: return x / y; 11: }; 12: double result = op1(10, 2); 13: 14: Console.WriteLine(result); 15: Console.ReadLine(); 16: } 17: 18: static double Division(double x, double y) { 19: return x / y; 20: } 21: } We could rewrite our delegate to be of a generic type like so (see line 2 and line 9). You will see why soon. 1: //Generic delegate 2: public delegate T Operation<T>(T x, T y); 3: 4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: Operation<double> op1 = delegate(double x, double y) { 10: return x / y; 11: }; 12: double result = op1(10, 2); 13: 14: Console.WriteLine(result); 15: Console.ReadLine(); 16: } 17: 18: static double Division(double x, double y) { 19: return x / y; 20: } 21: } The .NET 3.5 framework introduced a whole set of predefined delegates for us including public delegate TResult Func<T1, T2, TResult>(T1 arg1, T2 arg2); Our code can be modified to use this delegate instead of the one we declared. Our delegate declaration has been removed and line 7 has been changed to use the Func delegate type. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //Func is a delegate defined in the .NET 3.5 framework 7: Func<double, double, double> op1 = delegate (double x, double y) { 8: return x / y; 9: }; 10: double result = op1(10, 2); 11: 12: Console.WriteLine(result); 13: Console.ReadLine(); 14: } 15: 16: static double Division(double x, double y) { 17: return x / y; 18: } 19: } .NET 3.5 also introduced lambda expressions. A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. We change our code to use lambda expressions. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //lambda expression 7: Func<double, double, double> op1 = (x, y) => x / y; 8: double result = op1(10, 2); 9: 10: Console.WriteLine(result); 11: Console.ReadLine(); 12: } 13: 14: static double Division(double x, double y) { 15: return x / y; 16: } 17: } C# 3.0 introduced the keyword var (implicitly typed local variable) where the type of the variable is inferred based on the type of the associated initializer expression. We can rewrite our code to use var as shown below (line 7). The implicitly typed local variable op1 is inferred to be a delegate of type Func<double, double, double> at compile time. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //implicitly typed local variable 7: var op1 = (x, y) => x / y; 8: double result = op1(10, 2); 9: 10: Console.WriteLine(result); 11: Console.ReadLine(); 12: } 13: 14: static double Division(double x, double y) { 15: return x / y; 16: } 17: } You have seen how we can write code in fewer lines by using a combination of the Func delegate type, implicitly typed local variables and lambda expressions.

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IntelliSense for Razor Hosting in non-Web Applications

- by Rick Strahl

When I posted my Razor Hosting article a couple of weeks ago I got a number of questions on how to get IntelliSense to work inside of Visual Studio while editing your templates. The answer to this question is mainly dependent on how Visual Studio recognizes assemblies, so a little background is required. If you open a template just on its own as a standalone file by clicking on it say in Explorer, Visual Studio will open up with the template in the editor, but you won’t get any IntelliSense on any of your related assemblies that you might be using by default. It’ll give Intellisense on base System namespace, but not on your imported assembly types. This makes sense: Visual Studio has no idea what the assembly associations for the single file are. There are two options available to you to make IntelliSense work for templates: Add the templates as included files to your non-Web project Add a BIN folder to your template’s folder and add all assemblies required there Including Templates in your Host Project By including templates into your Razor hosting project, Visual Studio will pick up the project’s assembly references and make IntelliSense available for any of the custom types in your project and on your templates. To see this work I moved the \Templates folder from the samples from the Debug\Bin folder into the project root and included the templates in the WinForm sample project. Here’s what this looks like in Visual Studio after the templates have been included: Notice that I take my original example and type cast the Context object to the specific type that it actually represents – namely CustomContext – by using a simple code block: @{ CustomContext Model = Context as CustomContext; } After that assignment my Model local variable is in scope and IntelliSense works as expected. Note that you also will need to add any namespaces with the using command in this case: @using RazorHostingWinForm which has to be defined at the very top of a Razor document. BTW, while you can only pass in a single Context 'parameter’ to the template with the default template I’ve provided realize that you can also assign a complex object to Context. For example you could have a container object that references a variety of other objects which you can then cast to the appropriate types as needed: @{ ContextContainer container = Context as ContextContainer; CustomContext Model = container.Model; CustomDAO DAO = container.DAO; } and so forth. IntelliSense for your Custom Template Notice also that you can get IntelliSense for the top level template by specifying an inherits tag at the top of the document: @inherits RazorHosting.RazorTemplateFolderHost By specifying the above you can then get IntelliSense on your base template’s properties. For example, in my base template there are Request and Response objects. This is very useful especially if you end up creating custom templates that include your custom business objects as you can get effectively see full IntelliSense from the ‘page’ level down. For Html Help Builder for example, I’d have a Help object on the page and assuming I have the references available I can see all the way into that Help object without even having to do anything fancy. Note that the @inherits key is a GREAT and easy way to override the base template you normally specify as the default template. It allows you to create a custom template and as long as it inherits from the base template it’ll work properly. Since the last post I’ve also made some changes in the base template that allow hooking up some simple initialization logic so it gets much more easy to create custom templates and hook up custom objects with an IntializeTemplate() hook function that gets called with the Context and a Configuration object. These objects are objects you can pass in at runtime from your host application and then assign to custom properties on your template. For example the default implementation for RazorTemplateFolderHost does this: public override void InitializeTemplate(object context, object configurationData) { // Pick up configuration data and stuff into Request object RazorFolderHostTemplateConfiguration config = configurationData as RazorFolderHostTemplateConfiguration; this.Request.TemplatePath = config.TemplatePath; this.Request.TemplateRelativePath = config.TemplateRelativePath; // Just use the entire ConfigData as the model, but in theory // configData could contain many objects or values to set on // template properties this.Model = config.ConfigData as TModel; } to set up a strongly typed Model and the Request object. You can do much more complex hookups here of course and create complex base template pages that contain all the objects that you need in your code with strong typing. Adding a Bin folder to your Template’s Root Path Including templates in your host project works if you own the project and you’re the only one modifying the templates. However, if you are distributing the Razor engine as a templating/scripting solution as part of your application or development tool the original project is likely not available and so that approach is not practical. Another option you have is to add a Bin folder and add all the related assemblies into it. You can also add a Web.Config file with assembly references for any GAC’d assembly references that need to be associated with the templates. Between the web.config and bin folder Visual Studio can figure out how to provide IntelliSense. The Bin folder should contain: The RazorHosting.dll Your host project’s EXE or DLL – renamed to .dll if it’s an .exe Any external (bin folder) dependent assemblies Note that you most likely also want a reference to the host project if it contains references that are going to be used in templates. Visual Studio doesn’t recognize an EXE reference so you have to rename the EXE to DLL to make it work. Apparently the binary signature of EXE and DLL files are identical and it just works – learn something new everyday… For GAC assembly references you can add a web.config file to your template root. The Web.config file then should contain any full assembly references to GAC components: <configuration> <system.web> <compilation debug="true"> <assemblies> <add assembly="System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" /> <add assembly="System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" /> <add assembly="System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" /> </assemblies> </compilation> </system.web> </configuration> And with that you should get full IntelliSense. Note that if you add a BIN folder and you also have the templates in your Visual Studio project Visual Studio will complain about reference conflicts as it’s effectively seeing both the project references and the ones in the bin folder. So it’s probably a good idea to use one or the other but not both at the same time :-) Seeing IntelliSense in your Razor templates is a big help for users of your templates. If you’re shipping an application level scripting solution especially it’ll be real useful for your template consumers/users to be able to get some quick help on creating customized templates – after all that’s what templates are all about – easy customization. Making sure that everything is referenced in your bin folder and web.config is a good idea and it’s great to see that Visual Studio (and presumably WebMatrix/Visual Web Developer as well) will be able to pick up your custom IntelliSense in Razor templates.© Rick Strahl, West Wind Technologies, 2005-2011Posted in Razor

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Checking who is connected to your server, with PowerShell.

- by Fatherjack

There are many occasions when, as a DBA, you want to see who is connected to your SQL Server, along with how they are connecting and what sort of activities they are carrying out. I’m going to look at a couple of ways of getting this information and compare the effort required and the results achieved of each. SQL Server comes with a couple of stored procedures to help with this sort of task – sp_who and its undocumented counterpart sp_who2. There is also the pumped up version of these called sp_whoisactive, written by Adam Machanic which does way more than these procedures. I wholly recommend you try it out if you don’t already know how it works. When it comes to serious interrogation of your SQL Server activity then it is absolutely indispensable. Anyway, back to the point of this blog, we are going to look at getting the information from sp_who2 for a remote server. I wrote this Powershell script a week or so ago and was quietly happy with it for a while. I’m relatively new to Powershell so forgive both my rather low threshold for entertainment and the fact that something so simple is a moderate achievement for me. $Server = 'SERVERNAME' $SMOServer = New-Object Microsoft.SQLServer.Management.SMO.Server $Server # connection and query stuff $ConnectionStr = "Server=$Server;Database=Master;Integrated Security=True" $Query = "EXEC sp_who2" $Connection = new-object system.Data.SQLClient.SQLConnection $Table = new-object "System.Data.DataTable" $Connection.connectionstring = $ConnectionStr try{ $Connection.open() $Command = $Connection.CreateCommand() $Command.commandtext = $Query $result = $Command.ExecuteReader() $Table.Load($result) } catch{ # Show error $error[0] | format-list -Force } $Title = "Data access processes (" + $Table.Rows.Count + ")" $Table | Out-GridView -Title $Title $Connection.close() So this is pretty straightforward, create an SMO object that represents our chosen server, define a connection to the database and a table object for the results when we get them, execute our query over the connection, load the results into our table object and then, if everything is error free display these results to the PowerShell grid viewer. The query simply gets the results of ‘EXEC sp_who2′ for us. Depending on how many connections there are will influence how long the query runs. The grid viewer lets me sort and search the results so it can be a pretty handy way to locate troublesome connections. Like I say, I was quite pleased with this, it seems a pretty simple script and was working well for me, I have added a few parameters to control the output and give me more specific details but then I see a script that uses the $SMOServer object itself to provide the process information and saves having to define the connection object and query specifications. $Server = 'SERVERNAME' $SMOServer = New-Object Microsoft.SQLServer.Management.SMO.Server $Server $Processes = $SMOServer.EnumProcesses() $Title = "SMO processes (" + $Processes.Rows.Count + ")" $Processes | Out-GridView -Title $Title Create the SMO object of our server and then call the EnumProcesses method to get all the process information from the server. Staggeringly simple! The results are a little different though. Some columns are the same and we can see the same basic information so my first thought was to which runs faster – so that I can get my results more quickly and also so that I place less stress on my server(s). PowerShell comes with a great way of testing this – the Measure-Command function. All you have to do is wrap your piece of code in Measure-Command {[your code here]} and it will spit out the time taken to execute the code. So, I placed both of the above methods of getting SQL Server process connections in two Measure-Command wrappers and pressed F5! The Powershell console goes blank for a while as the code is executed internally when Measure-Command is used but the grid viewer windows appear and the console shows this. You can take the output from Measure-Command and format it for easier reading but in a simple comparison like this we can simply cross refer the TotalMilliseconds values from the two result sets to see how the two methods performed. The query execution method (running EXEC sp_who2 ) is the first set of timings and the SMO EnumProcesses is the second. I have run these on a variety of servers and while the results vary from execution to execution I have never seen the SMO version slower than the other. The difference has varied and the time for both has ranged from sub-second as we see above to almost 5 seconds on other systems. This difference, I would suggest is partly due to the cost overhead of having to construct the data connection and so on where as the SMO EnumProcesses method has the connection to the server already in place and just needs to call back the process information. There is also the difference in the data sets to consider. Let’s take a look at what we get and where the two methods differ Query execution method (sp_who2) SMO EnumProcesses Description - Urn What looks like an XML or JSON representation of the server name and the process ID SPID Spid The process ID Status Status The status of the process Login Login The login name of the user executing the command HostName Host The name of the computer where the process originated BlkBy BlockingSpid The SPID of a process that is blocking this one DBName Database The database that this process is connected to Command Command The type of command that is executing CPUTime Cpu The CPU activity related to this process DiskIO - The Disk IO activity related to this process LastBatch - The time the last batch was executed from this process. ProgramName Program The application that is facilitating the process connection to the SQL Server. SPID1 - In my experience this is always the same value as SPID. REQUESTID - In my experience this is always 0 - Name In my experience this is always the same value as SPID and so could be seen as analogous to SPID1 from sp_who2 - MemUsage An indication of the memory used by this process but I don’t know what it is measured in (bytes, Kb, Mb…) - IsSystem True or False depending on whether the process is internal to the SQL Server instance or has been created by an external connection requesting data. - ExecutionContextID In my experience this is always 0 so could be analogous to REQUESTID from sp_who2. Please note, these are my own very brief descriptions of these columns, detail can be found from MSDN for columns in the sp_who results here http://msdn.microsoft.com/en-GB/library/ms174313.aspx. Where the columns are common then I would use that description, in other cases then the information returned is purely for interpretation by the reader. Rather annoyingly both result sets have useful information that the other doesn’t. sp_who2 returns Disk IO and LastBatch information which is really useful but the SMO processes method give you IsSystem and MemUsage which have their place in fault diagnosis methods too. So which is better? On reflection I think I prefer to use the sp_who2 method primarily but knowing that the SMO Enumprocesses method is there when I need it is really useful and I’m sure I’ll use it regularly. I’m OK with the fact that it is the slower method because Measure-Command has shown me how close it is to the other option and that it really isn’t a large enough margin to matter.

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REST to Objects in C#

RESTful interfaces for web services are all the rage for many Web 2.0 sites. If you want to consume these in a very simple fashion, LINQ to XML can do the job pretty easily in C#. If you go searching for help on this, youll find a lot of incomplete solutions and fairly large toolkits and frameworks (guess how I know this) this quick article is meant to be a no fluff just stuff approach to making this work. POCO Objects Lets assume you have a Model that you want to suck data into from a RESTful web service. Ideally this is a Plain Old CLR Object, meaning it isnt infected with any persistence or serialization goop. It might look something like this: public class Entry { public int Id; public int UserId; public DateTime Date; public float Hours; public string Notes; public bool Billable; public override string ToString() { return String.Format("[{0}] User: {1} Date: {2} Hours: {3} Notes: {4} Billable {5}", Id, UserId, Date, Hours, Notes, Billable); } } Not that this isnt a completely trivial object. Lets look at the API for the service. RESTful HTTP Service In this case, its TickSpots API, with the following sample output: <?xml version="1.0" encoding="UTF-8"?> <entries type="array"> <entry> <id type="integer">24</id> <task_id type="integer">14</task_id> <user_id type="integer">3</user_id> <date type="date">2008-03-08</date> <hours type="float">1.00</hours> <notes>Had trouble with tribbles.</notes> <billable>true</billable> # Billable is an attribute inherited from the task <billed>true</billed> # Billed is an attribute to track whether the entry has been invoiced <created_at type="datetime">Tue, 07 Oct 2008 14:46:16 -0400</created_at> <updated_at type="datetime">Tue, 07 Oct 2008 14:46:16 -0400</updated_at> # The following attributes are derived and provided for informational purposes: <user_email>[email protected]</user_email> <task_name>Remove converter assembly</task_name> <sum_hours type="float">2.00</sum_hours> <budget type="float">10.00</budget> <project_name>Realign dilithium crystals</project_name> <client_name>Starfleet Command</client_name> </entry> </entries> Im assuming in this case that I dont necessarily care about all of the data fields the service is returning I just need some of them for my applications purposes. Thus, you can see there are more elements in the <entry> XML than I have in my Entry class. Get The XML with C# The next step is to get the XML. The following snippet does the heavy lifting once you pass it the appropriate URL: protected XElement GetResponse(string uri) { var request = WebRequest.Create(uri) as HttpWebRequest; request.UserAgent = ".NET Sample"; request.KeepAlive = false; request.Timeout = 15 * 1000; var response = request.GetResponse() as HttpWebResponse; if (request.HaveResponse == true && response != null) { var reader = new StreamReader(response.GetResponseStream()); return XElement.Parse(reader.ReadToEnd()); } throw new Exception("Error fetching data."); } This is adapted from the Yahoo Developer article on Web Service REST calls. Once you have the XML, the last step is to get the data back as your POCO. Use LINQ-To-XML to Deserialize POCOs from XML This is done via the following code: public IEnumerable<Entry> List(DateTime startDate, DateTime endDate) { string additionalParameters = String.Format("start_date={0}&end_date={1}", startDate.ToShortDateString(), endDate.ToShortDateString()); string uri = BuildUrl("entries", additionalParameters); XElement elements = GetResponse(uri); var entries = from e in elements.Elements() where e.Name.LocalName == "entry" select new Entry { Id = int.Parse(e.Element("id").Value), UserId = int.Parse(e.Element("user_id").Value), Date = DateTime.Parse(e.Element("date").Value), Hours = float.Parse(e.Element("hours").Value), Notes = e.Element("notes").Value, Billable = bool.Parse(e.Element("billable").Value) }; return entries; } For completeness, heres the BuildUrl method for my TickSpot API wrapper: // Change these to your settings protected const string projectDomain = "DOMAIN.tickspot.com"; private const string authParams = "[email protected]&password=MyTickSpotPassword"; protected string BuildUrl(string apiMethod, string additionalParams) { if (projectDomain.Contains("DOMAIN")) { throw new ApplicationException("You must update your domain in ProjectRepository.cs."); } if (authParams.Contains("MyTickSpotPassword")) { throw new ApplicationException("You must update your email and password in ProjectRepository.cs."); } return string.Format("https://{0}/api/{1}?{2}&{3}", projectDomain, apiMethod, authParams, additionalParams); } Thats it! Now go forth and consume XML and map it to classes you actually want to work with. Have fun! Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Why do we (really) program to interfaces?

- by Kyle Burns

One of the earliest lessons I was taught in Enterprise development was "always program against an interface". This was back in the VB6 days and I quickly learned that no code would be allowed to move to the QA server unless my business objects and data access objects each are defined as an interface and have a matching implementation class. Why? "It's more reusable" was one answer. "It doesn't tie you to a specific implementation" a slightly more knowing answer. And let's not forget the discussion ending "it's a standard". The problem with these responses was that senior people didn't really understand the reason we were doing the things we were doing and because of that, we were entirely unable to realize the intent behind the practice - we simply used interfaces and had a bunch of extra code to maintain to show for it. It wasn't until a few years later that I finally heard the term "Inversion of Control". Simply put, "Inversion of Control" takes the creation of objects that used to be within the control (and therefore a responsibility of) of your component and moves it to some outside force. For example, consider the following code which follows the old "always program against an interface" rule in the manner of many corporate development shops: 1: ICatalog catalog = new Catalog(); 2: Category[] categories = catalog.GetCategories(); In this example, I met the requirement of the rule by declaring the variable as ICatalog, but I didn't hit "it doesn't tie you to a specific implementation" because I explicitly created an instance of the concrete Catalog object. If I want to test the functionality of the code I just wrote I have to have an environment in which Catalog can be created along with any of the resources upon which it depends (e.g. configuration files, database connections, etc) in order to test my functionality. That's a lot of setup work and one of the things that I think ultimately discourages real buy-in of unit testing in many development shops. So how do I test my code without needing Catalog to work? A very primitive approach I've seen is to change the line the instantiates catalog to read: 1: ICatalog catalog = new FakeCatalog(); once the test is run and passes, the code is switched back to the real thing. This obviously poses a huge risk for introducing test code into production and in my opinion is worse than just keeping the dependency and its associated setup work. Another popular approach is to make use of Factory methods which use an object whose "job" is to know how to obtain a valid instance of the object. Using this approach, the code may look something like this: 1: ICatalog catalog = CatalogFactory.GetCatalog(); The code inside the factory is responsible for deciding "what kind" of catalog is needed. This is a far better approach than the previous one, but it does make projects grow considerably because now in addition to the interface, the real implementation, and the fake implementation(s) for testing you have added a minimum of one factory (or at least a factory method) for each of your interfaces. Once again, developers say "that's too complicated and has me writing a bunch of useless code" and quietly slip back into just creating a new Catalog and chalking any test failures up to "it will probably work on the server". This is where software intended specifically to facilitate Inversion of Control comes into play. There are many libraries that take on the Inversion of Control responsibilities in .Net and most of them have many pros and cons. From this point forward I'll discuss concepts from the standpoint of the Unity framework produced by Microsoft's Patterns and Practices team. I'm primarily focusing on this library because it questions about it inspired this posting. At Unity's core and that of most any IoC framework is a catalog or registry of components. This registry can be configured either through code or using the application's configuration file and in the most simple terms says "interface X maps to concrete implementation Y". It can get much more complicated, but I want to keep things at the "what does it do" level instead of "how does it do it". The object that exposes most of the Unity functionality is the UnityContainer. This object exposes methods to configure the catalog as well as the Resolve<T> method which is used to obtain an instance of the type represented by T. When using the Resolve<T> method, Unity does not necessarily have to just "new up" the requested object, but also can track dependencies of that object and ensure that the entire dependency chain is satisfied. There are three basic ways that I have seen Unity used within projects. Those are through classes directly using the Unity container, classes requiring injection of dependencies, and classes making use of the Service Locator pattern. The first usage of Unity is when classes are aware of the Unity container and directly call its Resolve method whenever they need the services advertised by an interface. The up side of this approach is that IoC is utilized, but the down side is that every class has to be aware that Unity is being used and tied directly to that implementation. Many developers don't like the idea of as close a tie to specific IoC implementation as is represented by using Unity within all of your classes and for the most part I agree that this isn't a good idea. As an alternative, classes can be designed for Dependency Injection. Dependency Injection is where a force outside the class itself manipulates the object to provide implementations of the interfaces that the class needs to interact with the outside world. This is typically done either through constructor injection where the object has a constructor that accepts an instance of each interface it requires or through property setters accepting the service providers. When using dependency, I lean toward the use of constructor injection because I view the constructor as being a much better way to "discover" what is required for the instance to be ready for use. During resolution, Unity looks for an injection constructor and will attempt to resolve instances of each interface required by the constructor, throwing an exception of unable to meet the advertised needs of the class. The up side of this approach is that the needs of the class are very clearly advertised and the class is unaware of which IoC container (if any) is being used. The down side of this approach is that you're required to maintain the objects passed to the constructor as instance variables throughout the life of your object and that objects which coordinate with many external services require a lot of additional constructor arguments (this gets ugly and may indicate a need for refactoring). The final way that I've seen and used Unity is to make use of the ServiceLocator pattern, of which the Patterns and Practices team has also provided a Unity-compatible implementation. When using the ServiceLocator, your class calls ServiceLocator.Retrieve in places where it would have called Resolve on the Unity container. Like using Unity directly, it does tie you directly to the ServiceLocator implementation and makes your code aware that dependency injection is taking place, but it does have the up side of giving you the freedom to swap out the underlying IoC container if necessary. I'm not hugely concerned with hiding IoC entirely from the class (I view this as a "nice to have"), so the single biggest problem that I see with the ServiceLocator approach is that it provides no way to proactively advertise needs in the way that constructor injection does, allowing more opportunity for difficult to track runtime errors. This blog entry has not been intended in any way to be a definitive work on IoC, but rather as something to spur thought about why we program to interfaces and some ways to reach the intended value of the practice instead of having it just complicate your code. I hope that it helps somebody begin or continue a journey away from being a "Cargo Cult Programmer".

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Execution plan warnings–The final chapter

- by Dave Ballantyne

In my previous posts (here and here), I showed examples of some of the execution plan warnings that have been added to SQL Server 2012. There is one other warning that is of interest to me : “Unmatched Indexes”. Firstly, how do I know this is the final one ? The plan is an XML document, right ? So that means that it can have an accompanying XSD. As an XSD is a schema definition, we can poke around inside it to find interesting things that *could* be in the final XML file. The showplan schema is stored in the folder Microsoft SQL Server\110\Tools\Binn\schemas\sqlserver\2004\07\showplan and by comparing schemas over releases you can get a really good idea of any new functionality that has been added. Here is the section of the Sql Server 2012 showplan schema that has been interesting me so far : <xsd:complexType name="AffectingConvertWarningType"> <xsd:annotation> <xsd:documentation>Warning information for plan-affecting type conversion</xsd:documentation> </xsd:annotation> <xsd:sequence>  </xsd:sequence> <xsd:attribute name="ConvertIssue" use="required"> <xsd:simpleType> <xsd:restriction base="xsd:string"> <xsd:enumeration value="Cardinality Estimate" /> <xsd:enumeration value="Seek Plan" />  </xsd:restriction> </xsd:simpleType> </xsd:attribute> <xsd:attribute name="Expression" type ="xsd:string" use="required" /></xsd:complexType><xsd:complexType name="WarningsType"> <xsd:annotation> <xsd:documentation>List of all possible iterator or query specific warnings (e.g. hash spilling, no join predicate)</xsd:documentation> </xsd:annotation> <xsd:choice minOccurs="1" maxOccurs="unbounded"> <xsd:element name="ColumnsWithNoStatistics" type="shp:ColumnReferenceListType" minOccurs="0" maxOccurs="1" /> <xsd:element name="SpillToTempDb" type="shp:SpillToTempDbType" minOccurs="0" maxOccurs="unbounded" /> <xsd:element name="Wait" type="shp:WaitWarningType" minOccurs="0" maxOccurs="unbounded" /> <xsd:element name="PlanAffectingConvert" type="shp:AffectingConvertWarningType" minOccurs="0" maxOccurs="unbounded" /> </xsd:choice> <xsd:attribute name="NoJoinPredicate" type="xsd:boolean" use="optional" /> <xsd:attribute name="SpatialGuess" type="xsd:boolean" use="optional" /> <xsd:attribute name="UnmatchedIndexes" type="xsd:boolean" use="optional" /> <xsd:attribute name="FullUpdateForOnlineIndexBuild" type="xsd:boolean" use="optional" /></xsd:complexType> I especially like the “to be extended here” comment, high hopes that we will see more of these in the future. So “Unmatched Indexes” was a warning that I couldn’t get and many thanks must go to Fabiano Amorim (b|t) for showing me the way. Filtered indexes were introduced in Sql Server 2008 and are really useful if you only need to index only a portion of the data within a table. However, if your SQL code uses a variable as a predicate on the filtered data that matches the filtered condition, then the filtered index cannot be used as, naturally, the value in the variable may ( and probably will ) change and therefore will need to read data outside the index. As an aside, you could use option(recompile) here , in which case the optimizer will build a plan specific to the variable values and use the filtered index, but that can bring about other problems. To demonstrate this warning, we need to generate some test data : DROP TABLE #TestTab1GOCREATE TABLE #TestTab1 (Col1 Int not null, Col2 Char(7500) not null, Quantity Int not null)GOINSERT INTO #TestTab1 VALUES (1,1,1),(1,2,5),(1,2,10),(1,3,20), (2,1,101),(2,2,105),(2,2,110),(2,3,120)GO and then add a filtered index CREATE INDEX ixFilter ON #TestTab1 (Col1)WHERE Quantity = 122 Now if we execute SELECT COUNT(*) FROM #TestTab1 WHERE Quantity = 122 We will see the filtered index being scanned But if we parameterize the query DECLARE @i INT = 122SELECT COUNT(*) FROM #TestTab1 WHERE Quantity = @i The plan is very different a table scan, as the value of the variable used in the predicate can change at run time, and also we see the familiar warning triangle. If we now look at the properties pane, we will see two pieces of information “Warnings” and “UnmatchedIndexes”. So, handily, we are being told which filtered index is not being used due to parameterization.

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REST to Objects in C#

RESTful interfaces for web services are all the rage for many Web 2.0 sites. If you want to consume these in a very simple fashion, LINQ to XML can do the job pretty easily in C#. If you go searching for help on this, youll find a lot of incomplete solutions and fairly large toolkits and frameworks (guess how I know this) this quick article is meant to be a no fluff just stuff approach to making this work. POCO Objects Lets assume you have a Model that you want to suck data into from a RESTful web service. Ideally this is a Plain Old CLR Object, meaning it isnt infected with any persistence or serialization goop. It might look something like this: public class Entry { public int Id; public int UserId; public DateTime Date; public float Hours; public string Notes; public bool Billable; public override string ToString() { return String.Format("[{0}] User: {1} Date: {2} Hours: {3} Notes: {4} Billable {5}", Id, UserId, Date, Hours, Notes, Billable); } } Not that this isnt a completely trivial object. Lets look at the API for the service. RESTful HTTP Service In this case, its TickSpots API, with the following sample output: <?xml version="1.0" encoding="UTF-8"?> <entries type="array"> <entry> <id type="integer">24</id> <task_id type="integer">14</task_id> <user_id type="integer">3</user_id> <date type="date">2008-03-08</date> <hours type="float">1.00</hours> <notes>Had trouble with tribbles.</notes> <billable>true</billable> # Billable is an attribute inherited from the task <billed>true</billed> # Billed is an attribute to track whether the entry has been invoiced <created_at type="datetime">Tue, 07 Oct 2008 14:46:16 -0400</created_at> <updated_at type="datetime">Tue, 07 Oct 2008 14:46:16 -0400</updated_at> # The following attributes are derived and provided for informational purposes: <user_email>[email protected]</user_email> <task_name>Remove converter assembly</task_name> <sum_hours type="float">2.00</sum_hours> <budget type="float">10.00</budget> <project_name>Realign dilithium crystals</project_name> <client_name>Starfleet Command</client_name> </entry> </entries> Im assuming in this case that I dont necessarily care about all of the data fields the service is returning I just need some of them for my applications purposes. Thus, you can see there are more elements in the <entry> XML than I have in my Entry class. Get The XML with C# The next step is to get the XML. The following snippet does the heavy lifting once you pass it the appropriate URL: protected XElement GetResponse(string uri) { var request = WebRequest.Create(uri) as HttpWebRequest; request.UserAgent = ".NET Sample"; request.KeepAlive = false; request.Timeout = 15 * 1000; var response = request.GetResponse() as HttpWebResponse; if (request.HaveResponse == true && response != null) { var reader = new StreamReader(response.GetResponseStream()); return XElement.Parse(reader.ReadToEnd()); } throw new Exception("Error fetching data."); } This is adapted from the Yahoo Developer article on Web Service REST calls. Once you have the XML, the last step is to get the data back as your POCO. Use LINQ-To-XML to Deserialize POCOs from XML This is done via the following code: public IEnumerable<Entry> List(DateTime startDate, DateTime endDate) { string additionalParameters = String.Format("start_date={0}&end_date={1}", startDate.ToShortDateString(), endDate.ToShortDateString()); string uri = BuildUrl("entries", additionalParameters); XElement elements = GetResponse(uri); var entries = from e in elements.Elements() where e.Name.LocalName == "entry" select new Entry { Id = int.Parse(e.Element("id").Value), UserId = int.Parse(e.Element("user_id").Value), Date = DateTime.Parse(e.Element("date").Value), Hours = float.Parse(e.Element("hours").Value), Notes = e.Element("notes").Value, Billable = bool.Parse(e.Element("billable").Value) }; return entries; } For completeness, heres the BuildUrl method for my TickSpot API wrapper: // Change these to your settings protected const string projectDomain = "DOMAIN.tickspot.com"; private const string authParams = "[email protected]&password=MyTickSpotPassword"; protected string BuildUrl(string apiMethod, string additionalParams) { if (projectDomain.Contains("DOMAIN")) { throw new ApplicationException("You must update your domain in ProjectRepository.cs."); } if (authParams.Contains("MyTickSpotPassword")) { throw new ApplicationException("You must update your email and password in ProjectRepository.cs."); } return string.Format("https://{0}/api/{1}?{2}&{3}", projectDomain, apiMethod, authParams, additionalParams); } Thats it! Now go forth and consume XML and map it to classes you actually want to work with. Have fun! Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Are you reporting Visual Studio 2012 issues to Microsoft correctly?

- by Tarun Arora

Issues you may run into while using Visual Studio need to be reported to the Microsoft Product Team via the Microsoft connect site. The Microsoft team then tries to reproduce the issue using the details provided by you. If the information you provide isn’t sufficient to reproduce the issue the team tries to contact you for specifics, this not only increases the cycle time to resolution but the lack of communication also results in issues not being resolved. So, when I report an issue one part of me tells me to include as much detail about the issue as I can clubbing screen shots, repo steps, system information, visual studio version information,… the other half tells me this is so time consuming, leave it for now and come back to fill all these details later. Reporting a bug but not including the supporting information is an invitation to excuses like … Microsoft has absolutely changed this experience for VS 2012. The Microsoft Visual Studio Feedback tool is designed to simplify the process of providing feedback and reporting issues to Microsoft that you may encounter while using Microsoft Visual Studio 2012. Note – The Microsoft Visual Studio 2012 Feedback client currently only works for VS 2012 and not any other versions of Visual Studio. Setting up the Microsoft Visual Studio 2012 Feedback client Open Visual Studio, from the Tools menu select Extension and Updates. In the Extension and Updates window, click Online from the left pane and search using the text ‘feedback’, download and Install Microsoft Visual Studio 2012 Feedback Tool by following the instructions from the wizard. Note - Restarting Visual Studio after the install is a must! How to report a bug for Visual Studio 2012? Click on the Help menu and choose Report a Bug You should see an icon Microsoft Visual Studio 2012 Feedback Tool come up in the system tray icon area You’ll need to accept the Privacy statement. You have the option of reporting the feedback as private or public. Microsoft works with several Partners, MVP’s and Vendors who get access to early bits of Microsoft products for valuation. This is where it becomes essential to report the feedback privately. I would choose the Public option otherwise. After all if it’s out there in the public, others can discover and add to it easily. You now have the option to report a new issue or add to an existing issue. Should you choose to add to an existing issue you should have the feedback ID of the issue available. This can be obtained from the Microsoft Connect site. For now I am going to focus on reporting a new feedback privately. Filling out the feedback details You will notice that VsInfo.xml and DxDiagOutput.txt are automatically attached as you enter this screen (more on that later). Feedback Type Choose the feedback type from (Performance, Hang, Crash, Other) Note – The record button will only be enabled once you have enabled once you have chosen the feedback type, Bug-repro recording is not available for Windows Server 2008. Effective Title and Description Enter a title that helps us differentiate the bug when it appears in a list, so that we can group it with any related bugs, assign it to a developer more effectively, and resolve it more quickly. Example: Imagine that you are submitting a bug because you tried to install Service Pack 1 and got a message that Visual Studio is not installed even though it is. Helpful: Installed Visual Studio version not detected during Service Pack 1 setup. Not helpful: Service Pack 1 problem. Tip: Write the problem description first, and then distil it to create a title. Example Description: Helpful: When I run Service Pack 1 Setup, I get the message "No Visual Studio version is detected" even though I have Visual Studio 2010 Ultimate and Visual C++ 2010 Express installed on my machine. Even though I uninstalled both editions, and then first reinstalled Ultimate and then Express, I still get the message. Record: Becoming a first class citizen Often a repro report is invaluable to describe and decipher the issue. Please use this feature to send actionable feedback. The record repro feature works differently depending on the feedback type you selected. Please find below details for each recording option. You can start recording simply by selecting a feedback type, and clicking on the “Record” button. When "Performance" is the bug type: When the Microsoft Visual Studio trace recorder starts, perform the actions that show the performance problem you want to report and then click on the "Stop Recording" button as soon as you experience the performance problem. Because the tool optimizes trace collection, you can run it for as long as it takes to show the problem, up to two hours. Note that, you need to stop recording as soon as the performance issue occurs, because the tool captures only the last couple minutes of your actions to optimize the trace collection. After you stop the recording, the tool takes up to two minutes to assemble the data and attach an ETLTrace.zip file to your bug report. The data includes information about Windows events and the Visual Studio code path. Note that, running the Microsoft Visual Studio trace recorder requires elevated user privilege. When "Crash" is the bug type: When the dialog box appears, select the running Visual Studio instance for which you want to show the steps that cause a crash. When the crash occurs, click on the "Stop Record" button. After you do this, two files are attached to your bug report - an AutomaticCrashDump.zip file that contains information about the crash and a ReproSteps.zip file that shows the repro steps. Repro steps are captured by Windows Problem Steps Recorder. Note that, you can pause the recording, and resume later, or for a specific step, you can add additional comments. When "Hang" is the bug type: The process for recording the steps that cause a hang resembles the one for crashes. The difference is, you can even collect a dump file after the VS hangs; start the VSFT either from the system tray or by starting a new instance of VS, select "Hang" as feedback type and click on the "Record" button. You will be prompted which VS to collect dump about, select the VS instance that hanged. VSFT collects a dump file regarding the hang, called MiniDump.zip, and attaches to your bug report. When "Other" is the bug type: When the problem step recorder starts, perform the actions that show the issue you want to report and then choose the "Stop” button. You can pause the recording, and resume later, or for a specific step, you can add additional comments. Once you’re done, ReproSteps.zip is added to your bug report. Pre-attached files It is essential for Microsoft to know what version of the the product are you currently using and what is the current configuration of your system. Note – The total size of all attachments in a bug report cannot exceed 2 GB, and every uncompressed attachment must be smaller than 512 MB. We recommend that you assemble all of your attachments, compress them together into a .zip file, and then attach the .zip file. Taking a screenshot Associate a screen shot by clicking the Take screenshot button, choose either the entire desktop, the specific monitor (useful if you are working in a multi monitor configuration) or the specific window in question. And finally … click Submit If you need further help, more details can be found here. You can view your feedback online by using the following URL “">https://connect.microsoft.com/VisualStudio/SearchResults.aspx?SearchQuery=<feedbackId>” Happy bug logging

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WiX 3 Tutorial: Custom EULA License and MSI localization

- by Mladen Prajdic

In this part of the ongoing Wix tutorial series we’ll take a look at how to localize your MSI into different languages. We’re still the mighty SuperForm: Program that takes care of all your label color needs. :) Localizing the MSI With WiX 3.0 localizing an MSI is pretty much a simple and straightforward process. First let look at the WiX project Properties->Build. There you can see "Cultures to build" textbox. Put specific cultures to build into the testbox or leave it empty to build all of them. Cultures have to be in correct culture format like en-US, en-GB or de-DE. Next we have to tell WiX which cultures we actually have in our project. Take a look at the first post in the series about Solution/Project structure and look at the Lang directory in the project structure picture. There we have de-de and en-us subfolders each with its own localized stuff. In the subfolders pay attention to the WXL files Loc_de-de.wxl and Loc_en-us.wxl. Each one has a <String Id="LANG"> under the WixLocalization root node. By including the string with id LANG we tell WiX we want that culture built. For English we have <String Id="LANG">1033</String>, for German <String Id="LANG">1031</String> in Loc_de-de.wxl and for French we’d have to create another file Loc_fr-FR.wxl and put <String Id="LANG">1036</String>. WXL files are localization files. Any string we want to localize we have to put in there. To reference it we use loc keyword like this: !(loc.IdOfTheVariable) => !(loc.MustCloseSuperForm) This is our Loc_en-us.wxl. Note that German wxl has an identical structure but values are in German. <?xml version="1.0" encoding="utf-8"?><WixLocalization Culture="en-us" xmlns="http://schemas.microsoft.com/wix/2006/localization" Codepage="1252"> <String Id="LANG">1033</String> <String Id="ProductName">SuperForm</String> <String Id="LicenseRtf" Overridable="yes">\Lang\en-us\EULA_en-us.rtf</String> <String Id="ManufacturerName">My Company Name</String> <String Id="AppNotSupported">This application is is not supported on your current OS. Minimal OS supported is Windows XP SP2</String> <String Id="DotNetFrameworkNeeded">.NET Framework 3.5 is required. Please install the .NET Framework then run this installer again.</String> <String Id="MustCloseSuperForm">Must close SuperForm!</String> <String Id="SuperFormNewerVersionInstalled">A newer version of !(loc.ProductName) is already installed.</String> <String Id="ProductKeyCheckDialog_Title">!(loc.ProductName) setup</String> <String Id="ProductKeyCheckDialogControls_Title">!(loc.ProductName) Product check</String> <String Id="ProductKeyCheckDialogControls_Description">Plese Enter following information to perform the licence check.</String> <String Id="ProductKeyCheckDialogControls_FullName">Full Name:</String> <String Id="ProductKeyCheckDialogControls_Organization">Organization:</String> <String Id="ProductKeyCheckDialogControls_ProductKey">Product Key:</String> <String Id="ProductKeyCheckDialogControls_InvalidProductKey">The product key you entered is invalid. Please call user support.</String> </WixLocalization> As you can see from the file we can use localization variables in other variables like we do for SuperFormNewerVersionInstalled string. ProductKeyCheckDialog* strings are to localize a custom dialog for Product key check which we’ll look at in the next post. Built in dialog text localization Under the de-de folder there’s also the WixUI_de-de.wxl file. This files contains German translations of all texts that are in WiX built in dialogs. It can be downloaded from WiX 3.0.5419.0 Source Forge site. Download the wix3-sources.zip and go to \src\ext\UIExtension\wixlib. There you’ll find already translated all WiX texts in 12 Languages. Localizing the custom EULA license Here it gets ugly. We can override the default EULA license easily by overriding WixUILicenseRtf WiX variable like this: <WixVariable Id="WixUILicenseRtf" Value="License.rtf" /> where License.rtf is the name of your custom EULA license file. The downside of this method is that you can only have one license file which means no localization for it. That’s why we need to make a workaround. License is checked on a dialog name LicenseAgreementDialog. What we have to do is overwrite that dialog and insert the functionality for localization. This is a code for LicenseAgreementDialogOverwritten.wxs, an overwritten LicenseAgreementDialog that supports localization. LicenseAcceptedOverwritten replaces the LicenseAccepted built in variable. <?xml version="1.0" encoding="UTF-8" ?><Wix xmlns="http://schemas.microsoft.com/wix/2006/wi"> <Fragment> <UI> <Dialog Id="LicenseAgreementDialogOverwritten" Width="370" Height="270" Title="!(loc.LicenseAgreementDlg_Title)"> <Control Id="LicenseAcceptedOverwrittenCheckBox" Type="CheckBox" X="20" Y="207" Width="330" Height="18" CheckBoxValue="1" Property="LicenseAcceptedOverwritten" Text="!(loc.LicenseAgreementDlgLicenseAcceptedCheckBox)" /> <Control Id="Back" Type="PushButton" X="180" Y="243" Width="56" Height="17" Text="!(loc.WixUIBack)" /> <Control Id="Next" Type="PushButton" X="236" Y="243" Width="56" Height="17" Default="yes" Text="!(loc.WixUINext)"> <Publish Event="SpawnWaitDialog" Value="WaitForCostingDlg">CostingComplete = 1</Publish> <Condition Action="disable"> <![CDATA[ LicenseAcceptedOverwritten <> "1" ]]> </Condition> <Condition Action="enable">LicenseAcceptedOverwritten = "1"</Condition> </Control> <Control Id="Cancel" Type="PushButton" X="304" Y="243" Width="56" Height="17" Cancel="yes" Text="!(loc.WixUICancel)"> <Publish Event="SpawnDialog" Value="CancelDlg">1</Publish> </Control> <Control Id="BannerBitmap" Type="Bitmap" X="0" Y="0" Width="370" Height="44" TabSkip="no" Text="!(loc.LicenseAgreementDlgBannerBitmap)" /> <Control Id="LicenseText" Type="ScrollableText" X="20" Y="60" Width="330" Height="140" Sunken="yes" TabSkip="no">    <Text SourceFile="$(var.ProjectDir)\!(loc.LicenseRtf)" />  </Control> <Control Id="Print" Type="PushButton" X="112" Y="243" Width="56" Height="17" Text="!(loc.WixUIPrint)"> <Publish Event="DoAction" Value="WixUIPrintEula">1</Publish> </Control> <Control Id="BannerLine" Type="Line" X="0" Y="44" Width="370" Height="0" /> <Control Id="BottomLine" Type="Line" X="0" Y="234" Width="370" Height="0" /> <Control Id="Description" Type="Text" X="25" Y="23" Width="340" Height="15" Transparent="yes" NoPrefix="yes" Text="!(loc.LicenseAgreementDlgDescription)" /> <Control Id="Title" Type="Text" X="15" Y="6" Width="200" Height="15" Transparent="yes" NoPrefix="yes" Text="!(loc.LicenseAgreementDlgTitle)" /> </Dialog> </UI> </Fragment></Wix> Look at the Control with Id "LicenseText” and read the comments. We’ve changed the original license text source to "$(var.ProjectDir)\!(loc.LicenseRtf)". var.ProjectDir is the directory of the project file. The !(loc.LicenseRtf) is where the magic happens. Scroll up and take a look at the wxl localization file example. We have the LicenseRtf declared there and it’s been made overridable so developers can change it if they want. The value of the LicenseRtf is the path to our localized EULA relative to the WiX project directory. With little hacking we’ve achieved a fully localizable installer package. The final step is to insert the extended LicenseAgreementDialogOverwritten license dialog into the installer GUI chain. This is how it’s done under the <UI> node of course. <UI>  <Publish Dialog="WelcomeDlg" Control="Next" Event="NewDialog" Value="LicenseAgreementDialogOverwritten">1</Publish> <Publish Dialog="LicenseAgreementDialogOverwritten" Control="Back" Event="NewDialog" Value="WelcomeDlg">1</Publish> <Publish Dialog="LicenseAgreementDialogOverwritten" Control="Next" Event="NewDialog" Value="ProductKeyCheckDialog">LicenseAcceptedOverwritten = "1" AND NOT OLDER_VERSION_FOUND</Publish> <Publish Dialog="InstallDirDlg" Control="Back" Event="NewDialog" Value="ProductKeyCheckDialog">1</Publish> </UI> For a thing that should be simple for the end developer to do, localization can be a bit advanced for the novice WiXer. Hope this post makes the journey easier and that next versions of WiX improve this process. WiX 3 tutorial by Mladen Prajdic navigation WiX 3 Tutorial: Solution/Project structure and Dev resources WiX 3 Tutorial: Understanding main wxs and wxi file WiX 3 Tutorial: Generating file/directory fragments with Heat.exe WiX 3 Tutorial: Custom EULA License and MSI localization WiX 3 Tutorial: Product Key Check custom action WiX 3 Tutorial: Building an updater WiX 3 Tutorial: Icons and installer pictures WiX 3 Tutorial: Creating a Bootstrapper

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Using LINQ Distinct: With an Example on ASP.NET MVC SelectListItem

- by Joe Mayo

One of the things that might be surprising in the LINQ Distinct standard query operator is that it doesn’t automatically work properly on custom classes. There are reasons for this, which I’ll explain shortly. The example I’ll use in this post focuses on pulling a unique list of names to load into a drop-down list. I’ll explain the sample application, show you typical first shot at Distinct, explain why it won’t work as you expect, and then demonstrate a solution to make Distinct work with any custom class. The technologies I’m using are LINQ to Twitter, LINQ to Objects, Telerik Extensions for ASP.NET MVC, ASP.NET MVC 2, and Visual Studio 2010. The function of the example program is to show a list of people that I follow. In Twitter API vernacular, these people are called “Friends”; though I’ve never met most of them in real life. This is part of the ubiquitous language of social networking, and Twitter in particular, so you’ll see my objects named accordingly. Where Distinct comes into play is because I want to have a drop-down list with the names of the friends appearing in the list. Some friends are quite verbose, which means I can’t just extract names from each tweet and populate the drop-down; otherwise, I would end up with many duplicate names. Therefore, Distinct is the appropriate operator to eliminate the extra entries from my friends who tend to be enthusiastic tweeters. The sample doesn’t do anything with the drop-down list and I leave that up to imagination for what it’s practical purpose could be; perhaps a filter for the list if I only want to see a certain person’s tweets or maybe a quick list that I plan to combine with a TextBox and Button to reply to a friend. When the program runs, you’ll need to authenticate with Twitter, because I’m using OAuth (DotNetOpenAuth), for authentication, and then you’ll see the drop-down list of names above the grid with the most recent tweets from friends. Here’s what the application looks like when it runs: As you can see, there is a drop-down list above the grid. The drop-down list is where most of the focus of this article will be. There is some description of the code before we talk about the Distinct operator, but we’ll get there soon. This is an ASP.NET MVC2 application, written with VS 2010. Here’s the View that produces this screen: <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<TwitterFriendsViewModel>" %> <%@ Import Namespace="DistinctSelectList.Models" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Home Page </asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <fieldset> <legend>Twitter Friends</legend> <div> <%= Html.DropDownListFor( twendVM => twendVM.FriendNames, Model.FriendNames, "<All Friends>") %> </div> <div> <% Html.Telerik().Grid<TweetViewModel>(Model.Tweets) .Name("TwitterFriendsGrid") .Columns(cols => { cols.Template(col => { %> <img src="<%= col.ImageUrl %>" alt="<%= col.ScreenName %>" /> <% }); cols.Bound(col => col.ScreenName); cols.Bound(col => col.Tweet); }) .Render(); %> </div> </fieldset> </asp:Content> As shown above, the Grid is from Telerik’s Extensions for ASP.NET MVC. The first column is a template that renders the user’s Avatar from a URL provided by the Twitter query. Both the Grid and DropDownListFor display properties that are collections from a TwitterFriendsViewModel class, shown below: using System.Collections.Generic; using System.Web.Mvc; namespace DistinctSelectList.Models { /// /// For finding friend info on screen /// public class TwitterFriendsViewModel { /// /// Display names of friends in drop-down list /// public List FriendNames { get; set; } /// /// Display tweets in grid /// public List Tweets { get; set; } } } I created the TwitterFreindsViewModel. The two Lists are what the View consumes to populate the DropDownListFor and Grid. Notice that FriendNames is a List of SelectListItem, which is an MVC class. Another custom class I created is the TweetViewModel (the type of the Tweets List), shown below: namespace DistinctSelectList.Models { /// /// Info on friend tweets /// public class TweetViewModel { /// /// User's avatar /// public string ImageUrl { get; set; } /// /// User's Twitter name /// public string ScreenName { get; set; } /// /// Text containing user's tweet /// public string Tweet { get; set; } } } The initial Twitter query returns much more information than we need for our purposes and this a special class for displaying info in the View. Now you know about the View and how it’s constructed. Let’s look at the controller next. The controller for this demo performs authentication, data retrieval, data manipulation, and view selection. I’ll skip the description of the authentication because it’s a normal part of using OAuth with LINQ to Twitter. Instead, we’ll drill down and focus on the Distinct operator. However, I’ll show you the entire controller, below, so that you can see how it all fits together: using System.Linq; using System.Web.Mvc; using DistinctSelectList.Models; using LinqToTwitter; namespace DistinctSelectList.Controllers { [HandleError] public class HomeController : Controller { private MvcOAuthAuthorization auth; private TwitterContext twitterCtx; /// /// Display a list of friends current tweets /// /// public ActionResult Index() { auth = new MvcOAuthAuthorization(InMemoryTokenManager.Instance, InMemoryTokenManager.AccessToken); string accessToken = auth.CompleteAuthorize(); if (accessToken != null) { InMemoryTokenManager.AccessToken = accessToken; } if (auth.CachedCredentialsAvailable) { auth.SignOn(); } else { return auth.BeginAuthorize(); } twitterCtx = new TwitterContext(auth); var friendTweets = (from tweet in twitterCtx.Status where tweet.Type == StatusType.Friends select new TweetViewModel { ImageUrl = tweet.User.ProfileImageUrl, ScreenName = tweet.User.Identifier.ScreenName, Tweet = tweet.Text }) .ToList(); var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct() .ToList(); var twendsVM = new TwitterFriendsViewModel { Tweets = friendTweets, FriendNames = friendNames }; return View(twendsVM); } public ActionResult About() { return View(); } } } The important part of the listing above are the LINQ to Twitter queries for friendTweets and friendNames. Both of these results are used in the subsequent population of the twendsVM instance that is passed to the view. Let’s dissect these two statements for clarification and focus on what is happening with Distinct. The query for friendTweets gets a list of the 20 most recent tweets (as specified by the Twitter API for friend queries) and performs a projection into the custom TweetViewModel class, repeated below for your convenience: var friendTweets = (from tweet in twitterCtx.Status where tweet.Type == StatusType.Friends select new TweetViewModel { ImageUrl = tweet.User.ProfileImageUrl, ScreenName = tweet.User.Identifier.ScreenName, Tweet = tweet.Text }) .ToList(); The LINQ to Twitter query above simplifies what we need to work with in the View and the reduces the amount of information we have to look at in subsequent queries. Given the friendTweets above, the next query performs another projection into an MVC SelectListItem, which is required for binding to the DropDownList. This brings us to the focus of this blog post, writing a correct query that uses the Distinct operator. The query below uses LINQ to Objects, querying the friendTweets collection to get friendNames: var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct() .ToList(); The above implementation of Distinct seems normal, but it is deceptively incorrect. After running the query above, by executing the application, you’ll notice that the drop-down list contains many duplicates. This will send you back to the code scratching your head, but there’s a reason why this happens. To understand the problem, we must examine how Distinct works in LINQ to Objects. Distinct has two overloads: one without parameters, as shown above, and another that takes a parameter of type IEqualityComparer<T>. In the case above, no parameters, Distinct will call EqualityComparer<T>.Default behind the scenes to make comparisons as it iterates through the list. You don’t have problems with the built-in types, such as string, int, DateTime, etc, because they all implement IEquatable<T>. However, many .NET Framework classes, such as SelectListItem, don’t implement IEquatable<T>. So, what happens is that EqualityComparer<T>.Default results in a call to Object.Equals, which performs reference equality on reference type objects. You don’t have this problem with value types because the default implementation of Object.Equals is bitwise equality. However, most of your projections that use Distinct are on classes, just like the SelectListItem used in this demo application. So, the reason why Distinct didn’t produce the results we wanted was because we used a type that doesn’t define its own equality and Distinct used the default reference equality. This resulted in all objects being included in the results because they are all separate instances in memory with unique references. As you might have guessed, the solution to the problem is to use the second overload of Distinct that accepts an IEqualityComparer<T> instance. If you were projecting into your own custom type, you could make that type implement IEqualityComparer<T>, but SelectListItem belongs to the .NET Framework Class Library. Therefore, the solution is to create a custom type to implement IEqualityComparer<T>, as in the SelectListItemComparer class, shown below: using System.Collections.Generic; using System.Web.Mvc; namespace DistinctSelectList.Models { public class SelectListItemComparer : EqualityComparer { public override bool Equals(SelectListItem x, SelectListItem y) { return x.Value.Equals(y.Value); } public override int GetHashCode(SelectListItem obj) { return obj.Value.GetHashCode(); } } } The SelectListItemComparer class above doesn’t implement IEqualityComparer<SelectListItem>, but rather derives from EqualityComparer<SelectListItem>. Microsoft recommends this approach for consistency with the behavior of generic collection classes. However, if your custom type already derives from a base class, go ahead and implement IEqualityComparer<T>, which will still work. EqualityComparer is an abstract class, that implements IEqualityComparer<T> with Equals and GetHashCode abstract methods. For the purposes of this application, the SelectListItem.Value property is sufficient to determine if two items are equal. Since SelectListItem.Value is type string, the code delegates equality to the string class. The code also delegates the GetHashCode operation to the string class.You might have other criteria in your own object and would need to define what it means for your object to be equal. Now that we have an IEqualityComparer<SelectListItem>, let’s fix the problem. The code below modifies the query where we want distinct values: var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct(new SelectListItemComparer()) .ToList(); Notice how the code above passes a new instance of SelectListItemComparer as the parameter to the Distinct operator. Now, when you run the application, the drop-down list will behave as you expect, showing only a unique set of names. In addition to Distinct, other LINQ Standard Query Operators have overloads that accept IEqualityComparer<T>’s, You can use the same techniques as shown here, with SelectListItemComparer, with those other operators as well. Now you know how to resolve problems with getting Distinct to work properly and also have a way to fix problems with other operators that require equality comparisons. @JoeMayo

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Delphi Indy IDHTTP question

- by user327175

I am trying to get the captcha image from a AOL, and i keep getting an error 418. unit imageunit; /// /// h t t p s://new.aol.com/productsweb/ /// interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, IdIOHandler, IdIOHandlerSocket, IdIOHandlerStack, IdSSL, IdSSLOpenSSL, IdIntercept, IdZLibCompressorBase, IdCompressorZLib, IdCookieManager, IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient, IdHTTP,jpeg,GIFImg, ExtCtrls; type TForm2 = class(TForm) IdHTTP1: TIdHTTP; IdCookieManager1: TIdCookieManager; IdCompressorZLib1: TIdCompressorZLib; IdConnectionIntercept1: TIdConnectionIntercept; IdSSLIOHandlerSocketOpenSSL1: TIdSSLIOHandlerSocketOpenSSL; Panel1: TPanel; Image1: TImage; Panel2: TPanel; Button1: TButton; Edit1: TEdit; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form2: TForm2; implementation {$R *.dfm} procedure TForm2.Button1Click(Sender: TObject); var JPI : TJPEGImage; streamdata:TMemoryStream; begin streamdata := TMemoryStream.Create; try idhttp1.Get(edit1.Text, Streamdata); Except { Handle exceptions } On E : Exception Do Begin MessageDlg('Exception: '+E.Message,mtError, [mbOK], 0); End; End; //h t t p s://new.aol.com/productsweb/WordVerImage?20890843 //h t t p s://new.aol.com/productsweb/WordVerImage?91868359 /// /// gives error 418 unused /// streamdata.Position := 0; JPI := TJPEGImage.Create; Try JPI.LoadFromStream ( streamdata ); Finally Image1.Picture.Assign ( JPI ); JPI.Free; streamdata.Free; End; end; end. Form: object Form2: TForm2 Left = 0 Top = 0 Caption = 'Form2' ClientHeight = 247 ClientWidth = 480 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False PixelsPerInch = 96 TextHeight = 13 object Panel1: TPanel Left = 0 Top = 41 Width = 480 Height = 206 Align = alClient TabOrder = 0 ExplicitLeft = -8 ExplicitTop = 206 ExplicitHeight = 41 object Image1: TImage Left = 1 Top = 1 Width = 478 Height = 204 Align = alClient ExplicitLeft = 5 ExplicitTop = 17 ExplicitWidth = 200 ExplicitHeight = 70 end end object Panel2: TPanel Left = 0 Top = 0 Width = 480 Height = 41 Align = alTop TabOrder = 1 ExplicitLeft = 40 ExplicitTop = 32 ExplicitWidth = 185 object Button1: TButton Left = 239 Top = 6 Width = 75 Height = 25 Caption = 'Button1' TabOrder = 0 OnClick = Button1Click end object Edit1: TEdit Left = 16 Top = 8 Width = 217 Height = 21 TabOrder = 1 end end object IdHTTP1: TIdHTTP Intercept = IdConnectionIntercept1 IOHandler = IdSSLIOHandlerSocketOpenSSL1 MaxAuthRetries = 100 AllowCookies = True HandleRedirects = True RedirectMaximum = 100 ProxyParams.BasicAuthentication = False ProxyParams.ProxyPort = 0 Request.ContentLength = -1 Request.Accept = 'image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-s' + 'hockwave-flash, application/cade, application/xaml+xml, applicat' + 'ion/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-' + 'application, /' Request.BasicAuthentication = False Request.Referer = 'http://www.yahoo.com' Request.UserAgent = 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.1) Gecko/201001' + '22 firefox/3.6.1' HTTPOptions = [hoForceEncodeParams] CookieManager = IdCookieManager1 Compressor = IdCompressorZLib1 Left = 240 Top = 80 end object IdCookieManager1: TIdCookieManager Left = 360 Top = 136 end object IdCompressorZLib1: TIdCompressorZLib Left = 368 Top = 16 end object IdConnectionIntercept1: TIdConnectionIntercept Left = 304 Top = 72 end object IdSSLIOHandlerSocketOpenSSL1: TIdSSLIOHandlerSocketOpenSSL Intercept = IdConnectionIntercept1 MaxLineAction = maException Port = 0 DefaultPort = 0 SSLOptions.Mode = sslmUnassigned SSLOptions.VerifyMode = [] SSLOptions.VerifyDepth = 0 Left = 192 Top = 136 end end If you go to: h t t p s://new.aol.com/productsweb/ you will notice the captcha image has a url like: h t t p s://new.aol.com/productsweb/WordVerImage?91868359 I put that url in the edit box and get an error. What is wrong with this code.

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Silverlight Recruiting Application Part 6 - Adding an Interview Scheduling Module/View

Between the last post and this one I went ahead and carried the ideas for the Jobs module and view into the Applicants module and view- they're both doing more or less the same thing, except with different objects being at their core. Made for an easy cut-and-paste operation with a few items being switched from one to another. Now that we have the ability to add postings and applicants, wouldn't it be nice if we could schedule an interview? Of course it would! Scheduling Module I think you get the drift from previous posts that these project structures start looking somewhat similar. The interview scheduling module is no different than the rest- it gets a SchedulingModule.cs file at the root that inherits from IModule, and there is a single SchedulerView.xsml and SchedulerViewModel.cs setup for our V+VM. We have one unique concern as we enter into this- RadScheduler deals with AppointmentsSource, not ItemsSource, so there are some special considerations to take into account when planning this module. First, I need something which inherits from AppointmentBase. This is the core of the RadScheduler appointment, and if you are planning to do any form of custom appointment, you'll want it to inherit from this. Then you can add-on functionality as needed. Here is my addition to the mix, the InterviewAppointment: 01.public class InterviewAppointment : AppointmentBase 02.{ 03. private int _applicantID; 04. public int ApplicantID 05. { 06. get { return this._applicantID; } 07. set 08. { 09. if (_applicantID != value) 10. { 11. _applicantID = value; 12. OnPropertyChanged("ApplicantID"); 13. } 14. } 15. } 16. 17. private int _postingID; 18. public int PostingID 19. { 20. get { return _postingID; } 21. set 22. { 23. if (_postingID != value) 24. { 25. _postingID = value; 26. OnPropertyChanged("PostingID"); 27. } 28. } 29. } 30. 31. private string _body; 32. public string Body 33. { 34. get { return _body; } 35. set 36. { 37. if (_body != value) 38. { 39. _body = value; 40. OnPropertyChanged("Body"); 41. } 42. } 43. } 44. 45. private int _interviewID; 46. public int InterviewID 47. { 48. get { return _interviewID; } 49. set 50. { 51. if (_interviewID != value) 52. { 53. _interviewID = value; 54. OnPropertyChanged("InterviewID"); 55. } 56. } 57. } 58. 59. public override IAppointment Copy() 60. { 61. IAppointment appointment = new InterviewAppointment(); 62. appointment.CopyFrom(this); 63. return appointment; 64. } 65. 66. public override void CopyFrom(IAppointment other) 67. { 68. base.CopyFrom(other); 69. var appointment = other as InterviewAppointment; 70. if (appointment != null) 71. { 72. ApplicantID = appointment.ApplicantID; 73. PostingID = appointment.PostingID; 74. Body = appointment.Body; 75. InterviewID = appointment.InterviewID; 76. } 77. } 78.} Nothing too exciting going on here, we just make sure that our custom fields are persisted (specifically set in CopyFrom at the bottom) and notifications are fired- otherwise this ends up exactly like the standard appointment as far as interactions, etc. But if we've got custom appointment items... that also means we need to customize what our appointment dialog window will look like. Customizing the Edit Appointment Dialog This initially sounds a lot more intimidating than it really is. The first step here depends on what you're dealing with for theming, but for ease of everything I went ahead and extracted my templates in Blend for RadScheduler so I could modify it as I pleased. For the faint of heart, the RadScheduler template is a few thousand lines of goodness since there are some very complex things going on in that control. I've gone ahead and trimmed down the template parts I don't need as much as possible, so what is left is all that is relevant to the Edit Appointment Dialog. Here's the resulting Xaml, with line numbers, so I can explain further: 001.<UserControl.Resources> 002.  003. <helpers:DataContextProxy x:Key="DataContextProxy" /> 004. 005. <telerik:Windows7Theme x:Key="Theme" /> 006. <SolidColorBrush x:Key="DialogWindowBackground" 007. Color="White" /> 008. <SolidColorBrush x:Key="CategorySelectorBorderBrush" 009. Color="#FFB1B1B1" /> 010. <LinearGradientBrush x:Key="RadToolBar_InnerBackground" 011. EndPoint="0.5,1" 012. StartPoint="0.5,0"> 013. <GradientStop Color="#FFFDFEFF" 014. Offset="0" /> 015. <GradientStop Color="#FFDDE9F7" 016. Offset="1" /> 017. <GradientStop Color="#FFE6F0FA" 018. Offset="0.5" /> 019. <GradientStop Color="#FFDCE6F4" 020. Offset="0.5" /> 021. </LinearGradientBrush> 022. <Style x:Key="FormElementTextBlockStyle" 023. TargetType="TextBlock"> 024. <Setter Property="HorizontalAlignment" 025. Value="Right" /> 026. <Setter Property="VerticalAlignment" 027. Value="Top" /> 028. <Setter Property="Margin" 029. Value="15, 15, 0, 2" /> 030. </Style> 031. <Style x:Key="FormElementStyle" 032. TargetType="FrameworkElement"> 033. <Setter Property="Margin" 034. Value="10, 10, 0, 2" /> 035. </Style> 036. <SolidColorBrush x:Key="GenericShallowBorderBrush" 037. Color="#FF979994" /> 038. <telerik:BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" /> 039. <telerikScheduler:ImportanceToBooleanConverter x:Key="ImportanceToBooleanConverter" /> 040. <telerikScheduler:NullToVisibilityConverter x:Key="NullToVisibilityConverter" /> 041. <telerikScheduler:InvertedNullToVisibilityConverter x:Key="InvertedNullToVisibilityConverter" /> 042. <scheduler:ResourcesSeparatorConverter x:Key="ResourcesSeparatorConverter" /> 043. <DataTemplate x:Key="IconDataEditTemplate"> 044. <Image Source="/Telerik.Windows.Controls.Scheduler;component/Themes/Office/Images/cal.png" 045. Margin="3,3,0,0" 046. Width="16" 047. Height="16" /> 048. </DataTemplate> 049. <DataTemplate x:Key="SingleSelectionTemplate"> 050. <Grid VerticalAlignment="Stretch" 051. HorizontalAlignment="Stretch"> 052. <Grid.RowDefinitions> 053. <RowDefinition Height="Auto" /> 054. </Grid.RowDefinitions> 055. <Grid.ColumnDefinitions> 056. <ColumnDefinition Width="Auto" 057. MinWidth="84" /> 058. <ColumnDefinition Width="Auto" 059. MinWidth="200" /> 060. </Grid.ColumnDefinitions> 061. <TextBlock x:Name="SelectionNameLabel" 062. Margin="0,13,4,2" 063. Text="{Binding ResourceType.DisplayName}" 064. Style="{StaticResource FormElementTextBlockStyle}" 065. Grid.Column="0" /> 066. <telerikInput:RadComboBox ItemsSource="{Binding ResourceItems}" 067. Width="185" 068. Margin="5,10,20,2" 069. HorizontalAlignment="Left" 070. Grid.Column="1" 071. ClearSelectionButtonVisibility="Visible" 072. ClearSelectionButtonContent="Clear All" 073. DisplayMemberPath="Resource.DisplayName" 074. telerik:StyleManager.Theme="{StaticResource Theme}" 075. SelectedItem="{Binding SelectedItem, Mode=TwoWay}" /> 076. </Grid> 077. </DataTemplate> 078. <DataTemplate x:Key="MultipleSelectionTemplate"> 079. <Grid VerticalAlignment="Stretch" 080. HorizontalAlignment="Stretch"> 081. <Grid.RowDefinitions> 082. <RowDefinition Height="Auto" /> 083. </Grid.RowDefinitions> 084. <Grid.ColumnDefinitions> 085. <ColumnDefinition Width="Auto" 086. MinWidth="84" /> 087. <ColumnDefinition Width="Auto" 088. MinWidth="200" /> 089. </Grid.ColumnDefinitions> 090. <TextBlock x:Name="SelectionNameLabel" 091. Grid.Column="0" 092. Text="{Binding ResourceType.DisplayName}" 093. Margin="0,13,4,2" 094. Style="{StaticResource FormElementTextBlockStyle}" /> 095. <telerikInput:RadComboBox Grid.Column="1" 096. Width="185" 097. HorizontalAlignment="Left" 098. Margin="5,10,20,2" 099. ItemsSource="{Binding ResourceItems}" 100. SelectedIndex="{Binding SelectedIndex, Mode=TwoWay}" 101. ClearSelectionButtonVisibility="Visible" 102. ClearSelectionButtonContent="Clear All" 103. telerik:StyleManager.Theme="{StaticResource Theme}"> 104. <telerikInput:RadComboBox.ItemTemplate> 105. <DataTemplate> 106. <Grid HorizontalAlignment="Stretch" 107. VerticalAlignment="Stretch"> 108. <CheckBox VerticalAlignment="Center" 109. HorizontalContentAlignment="Stretch" 110. VerticalContentAlignment="Center" 111. IsChecked="{Binding IsChecked, Mode=TwoWay}" 112. Content="{Binding Resource.DisplayName}"> 113. <CheckBox.ContentTemplate> 114. <DataTemplate> 115. <TextBlock HorizontalAlignment="Stretch" 116. VerticalAlignment="Stretch" 117. Text="{Binding Content, RelativeSource={RelativeSource TemplatedParent}}" /> 118. </DataTemplate> 119. </CheckBox.ContentTemplate> 120. </CheckBox> 121. </Grid> 122. </DataTemplate> 123. </telerikInput:RadComboBox.ItemTemplate> 124. </telerikInput:RadComboBox> 125. </Grid> 126. </DataTemplate> 127. <scheduler:ResourceTypeTemplateSelector x:Key="ItemTemplateSelector" 128. MultipleSelectionTemplate="{StaticResource MultipleSelectionTemplate}" 129. SingleSelectionTemplate="{StaticResource SingleSelectionTemplate}" /> 130.  131. 132. <ControlTemplate x:Key="EditAppointmentTemplate" 133. TargetType="telerikScheduler:AppointmentDialogWindow"> 134. <StackPanel Background="{TemplateBinding Background}" 135. UseLayoutRounding="True"> 136. <StackPanel Grid.Row="0" 137. Orientation="Horizontal" 138. Background="{StaticResource RadToolBar_InnerBackground}" 139. Grid.ColumnSpan="2" 140. Height="0"> 141.  142. <Border Margin="1,1,0,0" 143. Background="#50000000" 144. HorizontalAlignment="Left" 145. VerticalAlignment="Center" 146. Width="2" 147. Height="16"> 148. <Border Margin="0,0,1,1" 149. Background="#80FFFFFF" 150. HorizontalAlignment="Left" 151. Width="1" /> 152. </Border> 153. <Border Margin="1,1,0,0" 154. Background="#50000000" 155. HorizontalAlignment="Left" 156. VerticalAlignment="Center" 157. Width="2" 158. Height="16"> 159. <Border Margin="0,0,1,1" 160. Background="#80FFFFFF" 161. HorizontalAlignment="Left" 162. Width="1" /> 163. </Border> 164. <TextBlock telerik:LocalizationManager.ResourceKey="ShowAs" 165. VerticalAlignment="Center" 166. Margin="5,0,0,0" /> 167. <telerikInput:RadComboBox ItemsSource="{TemplateBinding TimeMarkers}" 168. Width="100" 169. Height="20" 170. VerticalAlignment="Center" 171. Margin="5,0,0,0" 172. ClearSelectionButtonVisibility="Visible" 173. ClearSelectionButtonContent="Clear" 174. SelectedItem="{Binding TimeMarker,RelativeSource={RelativeSource TemplatedParent},Mode=TwoWay}" 175. telerik:StyleManager.Theme="{StaticResource Theme}"> 176. <telerikInput:RadComboBox.ItemTemplate> 177. <DataTemplate> 178. <StackPanel Orientation="Horizontal"> 179. <Rectangle Fill="{Binding TimeMarkerBrush}" 180. Margin="2" 181. Width="12" 182. Height="12" /> 183. <TextBlock Text="{Binding TimeMarkerName}" 184. Margin="2" /> 185. </StackPanel> 186. </DataTemplate> 187. </telerikInput:RadComboBox.ItemTemplate> 188. </telerikInput:RadComboBox> 189. <telerik:RadToggleButton x:Name="High" 190. BorderThickness="0" 191. Background="{StaticResource RadToolBar_InnerBackground}" 192. DataContext="{TemplateBinding EditedAppointment}" 193. telerik:StyleManager.Theme="{StaticResource Theme}" 194. IsChecked="{Binding Importance,Mode=TwoWay, Converter={StaticResource ImportanceToBooleanConverter},ConverterParameter=High}" 195. Margin="2,2,0,2" 196. Width="23" 197. Height="23" 198. HorizontalContentAlignment="Center" 199. ToolTipService.ToolTip="High importance" 200. CommandParameter="High" 201. Command="telerikScheduler:RadSchedulerCommands.SetAppointmentImportance"> 202. <StackPanel HorizontalAlignment="Center"> 203. <Path Stretch="Fill" 204. Height="10" 205. HorizontalAlignment="Center" 206. VerticalAlignment="Top" 207. Width="5.451" 208. Data="M200.39647,58.840393 C200.39337,58.336426 201.14566,57.683922 202.56244,57.684292 C204.06589,57.684685 204.73764,58.357765 204.72783,58.992363 C205.04649,61.795574 203.04713,64.181099 202.47388,66.133446 C201.93753,64.154961 199.9471,61.560352 200.39647,58.840393 z"> 209. <Path.Fill> 210. <LinearGradientBrush EndPoint="1.059,0.375" 211. StartPoint="-0.457,0.519"> 212. <GradientStop Color="#FFFF0606" 213. Offset="0.609" /> 214. <GradientStop Color="#FFBF0303" 215. Offset="0.927" /> 216. </LinearGradientBrush> 217. </Path.Fill> 218. </Path> 219. <Ellipse Height="3" 220. HorizontalAlignment="Center" 221. Margin="0,-1,0,0" 222. VerticalAlignment="Top" 223. Width="3"> 224. <Ellipse.Fill> 225. <RadialGradientBrush> 226. <GradientStop Color="#FFFF0606" 227. Offset="0" /> 228. <GradientStop Color="#FFBF0303" 229. Offset="1" /> 230. </RadialGradientBrush> 231. </Ellipse.Fill> 232. </Ellipse> 233. </StackPanel> 234. </telerik:RadToggleButton> 235. <telerik:RadToggleButton x:Name="Low" 236. HorizontalContentAlignment="Center" 237. BorderThickness="0" 238. Background="{StaticResource RadToolBar_InnerBackground}" 239. DataContext="{TemplateBinding EditedAppointment}" 240. IsChecked="{Binding Importance,Mode=TwoWay, Converter={StaticResource ImportanceToBooleanConverter},ConverterParameter=Low}" 241. Margin="0,2,0,2" 242. Width="23" 243. Height="23" 244. ToolTipService.ToolTip="Low importance" 245. CommandParameter="Low" 246. telerik:StyleManager.Theme="{StaticResource Theme}" 247. Command="telerikScheduler:RadSchedulerCommands.SetAppointmentImportance"> 248. <Path Stretch="Fill" 249. Height="12" 250. HorizontalAlignment="Center" 251. VerticalAlignment="Top" 252. Width="9" 253. Data="M222.40353,60.139881 L226.65768,60.139843 L226.63687,67.240196 L229.15347,67.240196 L224.37816,71.394943 L219.65274,67.240196 L222.37572,67.219345 z" 254. Stroke="#FF0365A7"> 255. <Path.Fill> 256. <LinearGradientBrush EndPoint="1.059,0.375" 257. StartPoint="-0.457,0.519"> 258. <GradientStop Color="#FFBBE4FF" /> 259. <GradientStop Color="#FF024572" 260. Offset="0.836" /> 261. <GradientStop Color="#FF43ADF4" 262. Offset="0.466" /> 263. </LinearGradientBrush> 264. </Path.Fill> 265. </Path> 266. </telerik:RadToggleButton> 267. </StackPanel > 268. <Border DataContext="{TemplateBinding EditedAppointment}" 269. Background="{Binding Category.CategoryBrush}" 270. Visibility="{Binding Category,Converter={StaticResource NullToVisibilityConverter}}" 271. CornerRadius="3" 272. Height="20" 273. Margin="5,10,5,0"> 274. <TextBlock Text="{Binding Category.DisplayName}" 275. VerticalAlignment="Center" 276. Margin="5,0,0,0" /> 277. </Border> 278. <Grid VerticalAlignment="Stretch" 279. HorizontalAlignment="Stretch" 280. DataContext="{TemplateBinding EditedAppointment}" 281. Background="{TemplateBinding Background}"> 282. <Grid.RowDefinitions> 283. <RowDefinition Height="Auto" /> 284. <RowDefinition Height="Auto" /> 285. <RowDefinition Height="Auto" /> 286. <RowDefinition Height="Auto" /> 287. <RowDefinition Height="Auto" /> 288. <RowDefinition Height="Auto" /> 289. <RowDefinition Height="Auto" /> 290. <RowDefinition Height="Auto" /> 291. <RowDefinition Height="Auto" /> 292. <RowDefinition Height="Auto" /> 293. </Grid.RowDefinitions> 294. <Grid.ColumnDefinitions> 295. <ColumnDefinition Width="Auto" 296. MinWidth="100" /> 297. <ColumnDefinition Width="Auto" 298. MinWidth="200" /> 299. </Grid.ColumnDefinitions> 300.  301. <TextBlock x:Name="SubjectLabel" 302. Grid.Row="0" 303. Grid.Column="0" 304. Margin="0,15,0,2" 305. telerik:LocalizationManager.ResourceKey="Subject" 306. Style="{StaticResource FormElementTextBlockStyle}" /> 307. <TextBox x:Name="Subject" 308. Grid.Row="0" 309. Grid.Column="1" 310. MinHeight="22" 311. Padding="4 2" 312. Width="340" 313. HorizontalAlignment="Left" 314. Text="{Binding Subject, Mode=TwoWay}" 315. MaxLength="255" 316. telerik:StyleManager.Theme="{StaticResource Theme}" 317. Margin="10,12,20,2" /> 318.  319. <TextBlock x:Name="DescriptionLabel" 320. Grid.Row="1" 321. Grid.Column="0" 322. Margin="0,13,0,2" 323. telerik:LocalizationManager.ResourceKey="Body" 324. Style="{StaticResource FormElementTextBlockStyle}" /> 325. <TextBox x:Name="Body" 326. VerticalAlignment="top" 327. Grid.Row="1" 328. Grid.Column="1" 329. Height="Auto" 330. MaxHeight="82" 331. Width="340" 332. HorizontalAlignment="Left" 333. MinHeight="22" 334. Padding="4 2" 335. TextWrapping="Wrap" 336. telerik:StyleManager.Theme="{StaticResource Theme}" 337. Text="{Binding Body, Mode=TwoWay}" 338. AcceptsReturn="true" 339. Margin="10,10,20,2" 340. HorizontalScrollBarVisibility="Auto" 341. VerticalScrollBarVisibility="Auto" /> 342.  343. <TextBlock x:Name="StartDateLabel" 344. Grid.Row="2" 345. Grid.Column="0" 346. Margin="0,13,0,2" 347. telerik:LocalizationManager.ResourceKey="StartTime" 348. Style="{StaticResource FormElementTextBlockStyle}" /> 349. <telerikScheduler:DateTimePicker x:Name="StartDateTime" 350. Height="22" 351. Grid.Row="2" 352. Grid.Column="1" 353. HorizontalAlignment="Left" 354. Margin="10,10,20,2" 355. Style="{StaticResource FormElementStyle}" 356. SelectedDateTime="{Binding Start, Mode=TwoWay}" 357. telerikScheduler:StartEndDatePicker.EndPicker="{Binding ElementName=EndDateTime}" 358. IsTabStop="False" 359. IsEnabled="False" /> 360. <TextBlock x:Name="EndDateLabel" 361. Grid.Row="3" 362. Grid.Column="0" 363. Margin="0,13,0,2" 364. telerik:LocalizationManager.ResourceKey="EndTime" 365. Style="{StaticResource FormElementTextBlockStyle}" /> 366. <telerikScheduler:DateTimePicker x:Name="EndDateTime" 367. Height="22" 368. Grid.Row="3" 369. Grid.Column="1" 370. HorizontalAlignment="Left" 371. Margin="10,10,20,2" 372. Style="{StaticResource FormElementStyle}" 373. IsTabStop="False" 374. IsEnabled="False" 375. SelectedDateTime="{Binding End, Mode=TwoWay}" /> 376.  377. <CheckBox x:Name="AllDayEventCheckbox" 378. IsChecked="{Binding IsAllDayEvent, Mode=TwoWay}" 379. Grid.Row="4" 380. Grid.Column="1" 381. Margin="10,10,20,2" 382. HorizontalAlignment="Left" 383. telerik:StyleManager.Theme="{StaticResource Theme}" 384. telerik:LocalizationManager.ResourceKey="AllDayEvent"> 385. <telerik:CommandManager.InputBindings> 386. <telerik:InputBindingCollection> 387. <telerik:MouseBinding Command="telerikScheduler:RadSchedulerCommands.ChangeTimePickersVisibility" 388. Gesture="LeftClick" /> 389. </telerik:InputBindingCollection> 390. </telerik:CommandManager.InputBindings> 391. </CheckBox> 392. <Grid Grid.Row="5" 393. Grid.ColumnSpan="2"> 394. <Grid.ColumnDefinitions> 395. <ColumnDefinition Width="Auto" 396. MinWidth="100" /> 397. <ColumnDefinition Width="Auto" 398. MinWidth="200" /> 399. </Grid.ColumnDefinitions> 400. <Grid.RowDefinitions> 401. <RowDefinition Height="Auto" /> 402. <RowDefinition Height="Auto" /> 403. </Grid.RowDefinitions> 404. <TextBlock Text="Applicant" 405. Margin="0,13,0,2" 406. Style="{StaticResource FormElementTextBlockStyle}" /> 407. <telerikInput:RadComboBox IsEditable="False" 408. Grid.Column="1" 409. Height="24" 410. VerticalAlignment="Center" 411. ItemsSource="{Binding Source={StaticResource DataContextProxy}, Path=DataSource.ApplicantList}" 412. SelectedValue="{Binding ApplicantID, Mode=TwoWay}" 413. SelectedValuePath="ApplicantID" 414. DisplayMemberPath="FirstName" /> 415. 416. <TextBlock Text="Job" 417. Margin="0,13,0,2" 418. Grid.Row="1" 419. Style="{StaticResource FormElementTextBlockStyle}" /> 420. <telerikInput:RadComboBox IsEditable="False" 421. Grid.Column="1" 422. Grid.Row="1" 423. Height="24" 424. VerticalAlignment="Center" 425. ItemsSource="{Binding Source={StaticResource DataContextProxy}, Path=DataSource.JobsList}" 426. SelectedValue="{Binding PostingID, Mode=TwoWay}" 427. SelectedValuePath="PostingID" 428. DisplayMemberPath="JobTitle"/> 429. </Grid> 430.  431. <Grid x:Name="ResourcesLayout" 432. Grid.Row="7" 433. Grid.Column="0" 434. Grid.ColumnSpan="2" 435. MaxHeight="130" 436. Margin="20,5,20,0"> 437. <Border Margin="0" 438. BorderThickness="1" 439. BorderBrush="{StaticResource GenericShallowBorderBrush}" 440. Visibility="{Binding ElementName=ResourcesScrollViewer, Path=ComputedVerticalScrollBarVisibility}"></Border> 441. <ScrollViewer x:Name="ResourcesScrollViewer" 442. IsTabStop="false" 443. Grid.Row="6" 444. Grid.Column="0" 445. Grid.ColumnSpan="2" 446. Margin="1" 447. telerik:StyleManager.Theme="{StaticResource Theme}" 448. VerticalScrollBarVisibility="Auto"> 449. <scheduler:ResourcesItemsControl x:Name="PART_Resources" 450. HorizontalAlignment="Left" 451. Padding="0,2,0,5" 452. IsTabStop="false" 453. ItemsSource="{TemplateBinding ResourceTypeModels}" 454. ItemTemplateSelector="{StaticResource ItemTemplateSelector}" /> 455. </ScrollViewer> 456. </Grid> 457. <StackPanel x:Name="FooterControls" 458. Margin="5 10 10 10" 459. Grid.Row="8" 460. Grid.Column="1" 461. HorizontalAlignment="Left" 462. Orientation="Horizontal"> 463. <telerik:RadButton x:Name="OKButton" 464. Margin="5" 465. Padding="10 0" 466. MinWidth="80" 467. Command="telerikScheduler:RadSchedulerCommands.SaveAppointment" 468. telerik:StyleManager.Theme="{StaticResource Theme}" 469. telerikNavigation:RadWindow.ResponseButton="Accept" 470. telerik:LocalizationManager.ResourceKey="SaveAndCloseCommandText"> 471. </telerik:RadButton> 472. <telerik:RadButton x:Name="CancelButton" 473. Margin="5" 474. Padding="10 0" 475. MinWidth="80" 476. telerik:LocalizationManager.ResourceKey="Cancel" 477. telerik:StyleManager.Theme="{StaticResource Theme}" 478. telerikNavigation:RadWindow.ResponseButton="Cancel" 479. Command="telerik:WindowCommands.Close"> 480. </telerik:RadButton> 481. </StackPanel> 482. </Grid> 483. <vsm:VisualStateManager.VisualStateGroups> 484. <vsm:VisualStateGroup x:Name="RecurrenceRuleState"> 485. <vsm:VisualState x:Name="RecurrenceRuleIsNull"> 486. <Storyboard> 487. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="StartDateTime" 488. Storyboard.TargetProperty="IsEnabled" 489. Duration="0"> 490. <DiscreteObjectKeyFrame KeyTime="0" 491. Value="True" /> 492. </ObjectAnimationUsingKeyFrames> 493. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="EndDateTime" 494. Storyboard.TargetProperty="IsEnabled" 495. Duration="0"> 496. <DiscreteObjectKeyFrame KeyTime="0" 497. Value="True" /> 498. </ObjectAnimationUsingKeyFrames> 499. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="AllDayEventCheckbox" 500. Storyboard.TargetProperty="IsEnabled" 501. Duration="0"> 502. <DiscreteObjectKeyFrame KeyTime="0" 503. Value="True" /> 504. </ObjectAnimationUsingKeyFrames> 505. </Storyboard> 506. </vsm:VisualState> 507. <vsm:VisualState x:Name="RecurrenceRuleIsNotNull"> 508. <Storyboard> 509. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="StartDateTime" 510. Storyboard.TargetProperty="IsEnabled" 511. Duration="0"> 512. <DiscreteObjectKeyFrame KeyTime="0" 513. Value="False" /> 514. </ObjectAnimationUsingKeyFrames> 515. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="EndDateTime" 516. Storyboard.TargetProperty="IsEnabled" 517. Duration="0"> 518. <DiscreteObjectKeyFrame KeyTime="0" 519. Value="False" /> 520. </ObjectAnimationUsingKeyFrames> 521. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="AllDayEventCheckbox" 522. Storyboard.TargetProperty="IsEnabled" 523. Duration="0"> 524. <DiscreteObjectKeyFrame KeyTime="0" 525. Value="False" /> 526. </ObjectAnimationUsingKeyFrames> 527. </Storyboard> 528. </vsm:VisualState> 529. </vsm:VisualStateGroup> 530. </vsm:VisualStateManager.VisualStateGroups> 531. </StackPanel> 532. </ControlTemplate> 533. <DataTemplate x:Key="AppointmentDialogWindowHeaderDataTemplate"> 534. <StackPanel Orientation="Horizontal" 535. MaxWidth="400"> 536. <TextBlock telerik:LocalizationManager.ResourceKey="Event" 537. Visibility="{Binding Appointment.IsAllDayEvent, Converter={StaticResource BooleanToVisibilityConverter}}" /> 538. <TextBlock telerik:LocalizationManager.ResourceKey="Appointment" 539. Visibility="{Binding Appointment.IsAllDayEvent, Converter={StaticResource InvertedBooleanToVisibilityConverter}}" /> 540. <TextBlock Text=" - " /> 541. <TextBlock x:Name="SubjectTextBlock" 542. Visibility="{Binding Appointment.Subject, Converter={StaticResource NullToVisibilityConverter}}" 543. Text="{Binding Appointment.Subject}" /> 544. <TextBlock telerik:LocalizationManager.ResourceKey="Untitled" 545. Visibility="{Binding Appointment.Subject, Converter={StaticResource InvertedNullToVisibilityConverter}}" /> 546. </StackPanel> 547. </DataTemplate> 548. <Style x:Key="EditAppointmentStyle" 549. TargetType="telerikScheduler:AppointmentDialogWindow"> 550. <Setter Property="IconTemplate" 551. Value="{StaticResource IconDataEditTemplate}" /> 552. <Setter Property="HeaderTemplate" 553. Value="{StaticResource AppointmentDialogWindowHeaderDataTemplate}" /> 554. <Setter Property="Background" 555. Value="{StaticResource DialogWindowBackground}" /> 556. <Setter Property="Template" 557. Value="{StaticResource EditAppointmentTemplate}" /> 558. </Style> 559.</UserControl.Resources> The first line there is the DataContextProxy I mentioned previously- we use that again to work a bit of magic in this template. Where we start getting into the dialog in question is line 132, but line 407 is where things start getting interesting. The ItemsSource is pointing at a list that exists in my ViewModel (or code-behind, if it is used as a DataContext), the SelectedValue is the item I am actually binding from the applicant (note the TwoWay binding), and SelectedValuePath and DisplayMemberPath ensure the proper applicant is being displayed from the collection. You will also see similar starting on line 420 where I do the same for the Jobs we'll be displaying. Just to wrap-up the Xaml, here's the RadScheduler declaraction that ties this all together and will be the main focus of our view: 01.<telerikScheduler:RadScheduler x:Name="xJobsScheduler" 02. Grid.Row="1" 03. Grid.Column="1" 04. Width="800" 05. MinWidth="600" 06. Height="500" 07. MinHeight="300" 08. AppointmentsSource="{Binding Interviews}" 09. EditAppointmentStyle="{StaticResource EditAppointmentStyle}" 10. command:AppointmentAddedEventClass.Command="{Binding AddAppointmentCommand}" 11. command:ApptCreatedEventClass.Command="{Binding ApptCreatingCommand}" 12. command:ApptEditedEventClass.Command="{Binding ApptEditedCommand}" 13. command:ApptDeletedEventClass.Command="{Binding ApptDeletedCommand}"> 14.</telerikScheduler:RadScheduler> Now, we get to the ViewModel and what it takes to get that rigged up. And for those of you who remember the jobs post, those command:s in the Xaml are pointing to attached behavior commands that reproduce the respective events. This becomes very handy when we're setting up the code-behind version. ;) ViewModel I've been liking this approach so far, so I'm going to put the entire ViewModel here and then go into the lines of interest. Of course, feel free to ask me questions about anything that isn't clear (by line number, ideally) so I can help out if I have missed anything important: 001.public class SchedulerViewModel : ViewModelBase 002.{ 003. private readonly IEventAggregator eventAggregator; 004. private readonly IRegionManager regionManager; 005. 006. public RecruitingContext context; 007. 008. private ObservableItemCollection<InterviewAppointment> _interviews = new ObservableItemCollection<InterviewAppointment>(); 009. public ObservableItemCollection<InterviewAppointment> Interviews 010. { 011. get { return _interviews; } 012. set 013. { 014. if (_interviews != value) 015. { 016. _interviews = value; 017. NotifyChanged("Interviews"); 018. } 019. } 020. } 021. 022. private QueryableCollectionView _jobsList; 023. public QueryableCollectionView JobsList 024. { 025. get { return this._jobsList; } 026. set 027. { 028. if (this._jobsList != value) 029. { 030. this._jobsList = value; 031. this.NotifyChanged("JobsList"); 032. } 033. } 034. } 035. 036. private QueryableCollectionView _applicantList; 037. public QueryableCollectionView ApplicantList 038. { 039. get { return _applicantList; } 040. set 041. { 042. if (_applicantList != value) 043. { 044. _applicantList = value; 045. NotifyChanged("ApplicantList"); 046. } 047. } 048. } 049. 050. public DelegateCommand<object> AddAppointmentCommand { get; set; } 051. public DelegateCommand<object> ApptCreatingCommand { get; set; } 052. public DelegateCommand<object> ApptEditedCommand { get; set; } 053. public DelegateCommand<object> ApptDeletedCommand { get; set; } 054. 055. public SchedulerViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 056. { 057. // set Unity items 058. this.eventAggregator = eventAgg; 059. this.regionManager = regionmanager; 060. 061. // load our context 062. context = new RecruitingContext(); 063. LoadOperation<Interview> loadOp = context.Load(context.GetInterviewsQuery()); 064. loadOp.Completed += new EventHandler(loadOp_Completed); 065. 066. this._jobsList = new QueryableCollectionView(context.JobPostings); 067. context.Load(context.GetJobPostingsQuery()); 068. 069. this._applicantList = new QueryableCollectionView(context.Applicants); 070. context.Load(context.GetApplicantsQuery()); 071. 072. AddAppointmentCommand = new DelegateCommand<object>(this.AddAppt); 073. ApptCreatingCommand = new DelegateCommand<object>(this.ApptCreating); 074. ApptEditedCommand = new DelegateCommand<object>(this.ApptEdited); 075. ApptDeletedCommand = new DelegateCommand<object>(this.ApptDeleted); 076. 077. } 078. 079. void loadOp_Completed(object sender, EventArgs e) 080. { 081. LoadOperation loadop = sender as LoadOperation; 082. 083. foreach (var ent in loadop.Entities) 084. { 085. _interviews.Add(EntityToAppointment(ent as Interview)); 086. } 087. } 088. 089. #region Appointment Adding 090. 091. public void AddAppt(object obj) 092. { 093. // now we have a new InterviewAppointment to add to our QCV :) 094. InterviewAppointment newInterview = obj as InterviewAppointment; 095. 096. this.context.Interviews.Add(AppointmentToEntity(newInterview)); 097. this.context.SubmitChanges((s) => 098. { 099. ActionHistory myAction = new ActionHistory(); 100. myAction.InterviewID = newInterview.InterviewID; 101. myAction.PostingID = newInterview.PostingID; 102. myAction.ApplicantID = newInterview.ApplicantID; 103. myAction.Description = String.Format("Interview with {0} has been created by {1}", newInterview.ApplicantID.ToString(), "default user"); 104. myAction.TimeStamp = DateTime.Now; 105. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 106. } 107. , null); 108. } 109. 110. public void ApptCreating(object obj) 111. { 112. // handled in the behavior, just a placeholder to ensure it runs :) 113. } 114. 115. #endregion 116. 117. #region Appointment Editing 118. 119. public void ApptEdited(object obj) 120. { 121. Interview editedInterview = (from x in context.Interviews 122. where x.InterviewID == (obj as InterviewAppointment).InterviewID 123. select x).SingleOrDefault(); 124. 125. CopyAppointmentEdit(editedInterview, obj as InterviewAppointment); 126. 127. context.SubmitChanges((s) => { 128. ActionHistory myAction = new ActionHistory(); 129. myAction.InterviewID = editedInterview.InterviewID; 130. myAction.PostingID = editedInterview.PostingID; 131. myAction.ApplicantID = editedInterview.ApplicantID; 132. myAction.Description = String.Format("Interview with {0} has been modified by {1}", editedInterview.ApplicantID.ToString(), "default user"); 133. myAction.TimeStamp = DateTime.Now; 134. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); } 135. , null); 136. } 137. 138. #endregion 139. 140. #region Appointment Deleting 141. 142. public void ApptDeleted(object obj) 143. { 144. Interview deletedInterview = (from x in context.Interviews 145. where x.InterviewID == (obj as InterviewAppointment).InterviewID 146. select x).SingleOrDefault(); 147. 148. context.Interviews.Remove(deletedInterview); 149. context.SubmitChanges((s) => 150. { 151. ActionHistory myAction = new ActionHistory(); 152. myAction.InterviewID = deletedInterview.InterviewID; 153. myAction.PostingID = deletedInterview.PostingID; 154. myAction.ApplicantID = deletedInterview.ApplicantID; 155. myAction.Description = String.Format("Interview with {0} has been deleted by {1}", deletedInterview.ApplicantID.ToString(), "default user"); 156. myAction.TimeStamp = DateTime.Now; 157. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 158. } 159. , null); 160. } 161. 162. #endregion 163. 164. #region Appointment Helpers :) 165. 166. public Interview AppointmentToEntity(InterviewAppointment ia) 167. { 168. Interview newInterview = new Interview(); 169. newInterview.Subject = ia.Subject; 170. newInterview.Body = ia.Body; 171. newInterview.Start = ia.Start; 172. newInterview.End = ia.End; 173. newInterview.ApplicantID = ia.ApplicantID; 174. newInterview.PostingID = ia.PostingID; 175. newInterview.InterviewID = ia.InterviewID; 176. 177. return newInterview; 178. } 179. 180. public InterviewAppointment EntityToAppointment(Interview ia) 181. { 182. InterviewAppointment newInterview = new InterviewAppointment(); 183. newInterview.Subject = ia.Subject; 184. newInterview.Body = ia.Body; 185. newInterview.Start = ia.Start; 186. newInterview.End = ia.End; 187. newInterview.ApplicantID = ia.ApplicantID; 188. newInterview.PostingID = ia.PostingID; 189. newInterview.InterviewID = ia.InterviewID; 190. 191. return newInterview; 192. } 193. 194. public void CopyAppointmentEdit(Interview entityInterview, InterviewAppointment appointmentInterview) 195. { 196. entityInterview.Subject = appointmentInterview.Subject; 197. entityInterview.Body = appointmentInterview.Body; 198. entityInterview.Start = appointmentInterview.Start; 199. entityInterview.End = appointmentInterview.End; 200. entityInterview.ApplicantID = appointmentInterview.ApplicantID; 201. entityInterview.PostingID = appointmentInterview.PostingID; 202. } 203. 204. #endregion 205.} One thing we're doing here which you won't see in any of the other ViewModels is creating a duplicate collection. I know this is something which will be fixed down the line for using RadScheduler, simplifying this process, but with WCF RIA changing as it does I wanted to ensure functionality would remain consistent as I continued development on this application. So, I do a little bit of duplication, but for the greater good. This all takes place starting on line 79, so for every entity that comes back we add it to the collection that is bound to RadScheduler. Otherwise, the DelegateCommands that you see correspond directly to the events they are named after. In each case, rather than sending over the full event arguments, I just send in the appointment in question (coming through as the object obj in all cases) so I can add (line 91), edit (line 119), and delete appointments (line 142) like normal. This just ensures they get updated back to my database. Also, the one bit of code you won't see is for the Appointment Creating (line 110) event- that is because in the command I've created I simply make the replacement I need to: 1.void element_AppointmentCreating(object sender, AppointmentCreatingEventArgs e) 2.{ 3. e.NewAppointment = new InterviewAppointment(); 4. base.ExecuteCommand(); 5.} And the ViewModel is none the wiser, the appointments just work as far as it is concerned since as they are created they become InterviewAppointments. End result? I've customized my EditAppointmentDialog as follows: And adding, editing, and deleting appointments works like a charm. I can even 'edit' by moving appointments around RadScheduler, so as they are dropped into a timeslot they perform their full edit routine and things get updated. And then, the Code-Behind Version Perhaps the thing I like the most about doing one then the other is I get to steal 90% or more of the code from the MVVM version. For example, the only real changes to the Code-Behind Xaml file exist in the control declaration, in which I use events instead of attached-behavior-event-commands: 01.<telerikScheduler:RadScheduler x:Name="xJobsScheduler" 02. Grid.Row="1" 03. Grid.Column="1" 04. Width="800" 05. MinWidth="600" 06. Height="500" 07. MinHeight="300" 08. EditAppointmentStyle="{StaticResource EditAppointmentStyle}" 09. AppointmentAdded="xJobsScheduler_AppointmentAdded" 10. AppointmentCreating="xJobsScheduler_AppointmentCreating" 11. AppointmentEdited="xJobsScheduler_AppointmentEdited" 12. AppointmentDeleted="xJobsScheduler_AppointmentDeleted"> 13.</telerikScheduler:RadScheduler> Easy, right? Otherwise, all the same styling in UserControl.Resources was re-used, right down to the DataContextProxy that lets us bind to a collection from our viewmodel (in this case, our code-behind) to use within the DataTemplate. The code conversion gets even easier, as I could literally copy and paste almost everything from the ViewModel to my Code-Behind, just a matter of pasting the right section into the right event. Here's the code-behind as proof: 001.public partial class SchedulingView : UserControl, INotifyPropertyChanged 002.{ 003. public RecruitingContext context; 004. 005. private QueryableCollectionView _jobsList; 006. public QueryableCollectionView JobsList 007. { 008. get { return this._jobsList; } 009. set 010. { 011. if (this._jobsList != value) 012. { 013. this._jobsList = value; 014. this.NotifyChanged("JobsList"); 015. } 016. } 017. } 018. 019. private QueryableCollectionView _applicantList; 020. public QueryableCollectionView ApplicantList 021. { 022. get { return _applicantList; } 023. set 024. { 025. if (_applicantList != value) 026. { 027. _applicantList = value; 028. NotifyChanged("ApplicantList"); 029. } 030. } 031. } 032. 033. private ObservableItemCollection<InterviewAppointment> _interviews = new ObservableItemCollection<InterviewAppointment>(); 034. public ObservableItemCollection<InterviewAppointment> Interviews 035. { 036. get { return _interviews; } 037. set 038. { 039. if (_interviews != value) 040. { 041. _interviews = value; 042. NotifyChanged("Interviews"); 043. } 044. } 045. } 046. 047. public SchedulingView() 048. { 049. InitializeComponent(); 050. 051. this.DataContext = this; 052. 053. this.Loaded += new RoutedEventHandler(SchedulingView_Loaded); 054. } 055. 056. void SchedulingView_Loaded(object sender, RoutedEventArgs e) 057. { 058. this.xJobsScheduler.AppointmentsSource = Interviews; 059. 060. context = new RecruitingContext(); 061. 062. LoadOperation loadop = context.Load(context.GetInterviewsQuery()); 063. loadop.Completed += new EventHandler(loadop_Completed); 064. 065. this._applicantList = new QueryableCollectionView(context.Applicants); 066. context.Load(context.GetApplicantsQuery()); 067. 068. this._jobsList = new QueryableCollectionView(context.JobPostings); 069. context.Load(context.GetJobPostingsQuery()); 070. } 071. 072. void loadop_Completed(object sender, EventArgs e) 073. { 074. LoadOperation loadop = sender as LoadOperation; 075. 076. _interviews.Clear(); 077. 078. foreach (var ent in loadop.Entities) 079. { 080. _interviews.Add(EntityToAppointment(ent as Interview)); 081. } 082. } 083. 084. private void xJobsScheduler_AppointmentAdded(object sender, Telerik.Windows.Controls.AppointmentAddedEventArgs e) 085. { 086. // now we have a new InterviewAppointment to add to our QCV :) 087. InterviewAppointment newInterview = e.Appointment as InterviewAppointment; 088. 089. this.context.Interviews.Add(AppointmentToEntity(newInterview)); 090. this.context.SubmitChanges((s) => 091. { 092. ActionHistory myAction = new ActionHistory(); 093. myAction.InterviewID = newInterview.InterviewID; 094. myAction.PostingID = newInterview.PostingID; 095. myAction.ApplicantID = newInterview.ApplicantID; 096. myAction.Description = String.Format("Interview with {0} has been created by {1}", newInterview.ApplicantID.ToString(), "default user"); 097. myAction.TimeStamp = DateTime.Now; 098. context.ActionHistories.Add(myAction); 099. context.SubmitChanges(); 100. } 101. , null); 102. } 103. 104. private void xJobsScheduler_AppointmentCreating(object sender, Telerik.Windows.Controls.AppointmentCreatingEventArgs e) 105. { 106. e.NewAppointment = new InterviewAppointment(); 107. } 108. 109. private void xJobsScheduler_AppointmentEdited(object sender, Telerik.Windows.Controls.AppointmentEditedEventArgs e) 110. { 111. Interview editedInterview = (from x in context.Interviews 112. where x.InterviewID == (e.Appointment as InterviewAppointment).InterviewID 113. select x).SingleOrDefault(); 114. 115. CopyAppointmentEdit(editedInterview, e.Appointment as InterviewAppointment); 116. 117. context.SubmitChanges((s) => 118. { 119. ActionHistory myAction = new ActionHistory(); 120. myAction.InterviewID = editedInterview.InterviewID; 121. myAction.PostingID = editedInterview.PostingID; 122. myAction.ApplicantID = editedInterview.ApplicantID; 123. myAction.Description = String.Format("Interview with {0} has been modified by {1}", editedInterview.ApplicantID.ToString(), "default user"); 124. myAction.TimeStamp = DateTime.Now; 125. context.ActionHistories.Add(myAction); 126. context.SubmitChanges(); 127. } 128. , null); 129. } 130. 131. private void xJobsScheduler_AppointmentDeleted(object sender, Telerik.Windows.Controls.AppointmentDeletedEventArgs e) 132. { 133. Interview deletedInterview = (from x in context.Interviews 134. where x.InterviewID == (e.Appointment as InterviewAppointment).InterviewID 135. select x).SingleOrDefault(); 136. 137. context.Interviews.Remove(deletedInterview); 138. context.SubmitChanges((s) => 139. { 140. ActionHistory myAction = new ActionHistory(); 141. myAction.InterviewID = deletedInterview.InterviewID; 142. myAction.PostingID = deletedInterview.PostingID; 143. myAction.ApplicantID = deletedInterview.ApplicantID; 144. myAction.Description = String.Format("Interview with {0} has been deleted by {1}", deletedInterview.ApplicantID.ToString(), "default user"); 145. myAction.TimeStamp = DateTime.Now; 146. context.ActionHistories.Add(myAction); 147. context.SubmitChanges(); 148. } 149. , null); 150. } 151. 152. #region Appointment Helpers :) 153. 154. public Interview AppointmentToEntity(InterviewAppointment ia) 155. { 156. Interview newInterview = new Interview(); 157. newInterview.Subject = ia.Subject; 158. newInterview.Body = ia.Body; 159. newInterview.Start = ia.Start; 160. newInterview.End = ia.End; 161. newInterview.ApplicantID = ia.ApplicantID; 162. newInterview.PostingID = ia.PostingID; 163. newInterview.InterviewID = ia.InterviewID; 164. 165. return newInterview; 166. } 167. 168. public InterviewAppointment EntityToAppointment(Interview ia) 169. { 170. InterviewAppointment newInterview = new InterviewAppointment(); 171. newInterview.Subject = ia.Subject; 172. newInterview.Body = ia.Body; 173. newInterview.Start = ia.Start; 174. newInterview.End = ia.End; 175. newInterview.ApplicantID = ia.ApplicantID; 176. newInterview.PostingID = ia.PostingID; 177. newInterview.InterviewID = ia.InterviewID; 178. 179. return newInterview; 180. } 181. 182. public void CopyAppointmentEdit(Interview entityInterview, InterviewAppointment appointmentInterview) 183. { 184. entityInterview.Subject = appointmentInterview.Subject; 185. entityInterview.Body = appointmentInterview.Body; 186. entityInterview.Start = appointmentInterview.Start; 187. entityInterview.End = appointmentInterview.End; 188. entityInterview.ApplicantID = appointmentInterview.ApplicantID; 189. entityInterview.PostingID = appointmentInterview.PostingID; 190. } 191. 192. #endregion 193. 194. #region INotifyPropertyChanged Members 195. 196. public event PropertyChangedEventHandler PropertyChanged; 197. 198. public void NotifyChanged(string propertyName) 199. { 200. if (string.IsNullOrEmpty(propertyName)) 201. throw new ArgumentException("propertyName"); 202. 203. PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 204. } 205. 206. #endregion 207.} Nice... right? :) One really important thing to note as well. See on line 51 where I set the DataContext before the Loaded event? This is super important, as if you don't have this set before the usercontrol is loaded, the DataContextProxy has no context to use and your EditAppointmentDialog Job/Applicant dropdowns will be blank and empty. Trust me on this, took a little bit of debugging to figure out that by setting the DataContext post-loaded would only lead to disaster and frustration. Otherwise, the only other real difference is that instead of sending an ActionHistory item through an event to get added to the database and saved, I do those right in the callback from submitting. The Result Again, I only have to post one picture because these bad boys used nearly identical code for both the MVVM and the code-behind views, so our end result is... So what have we learned here today? One, for the most part this MVVM thing is somewhat easy. Yeah, you sometimes have to write a bunch of extra code, but with the help of a few useful snippits you can turn the process into a pretty streamlined little workflow. Heck, this story gets even easier as you can see in this blog post by Michael Washington- specifically run a find on 'InvokeCommandAction' and you'll see the section regarding the command on TreeView in Blend 4. Brilliant! MVVM never looked so sweet! Otherwise, it is business as usual with RadScheduler for Silverlight whichever path you're choosing for your development. Between now and the next post, I'll be cleaning up styles a bit (those RadComboBoxes are a little too close to my labels!) and adding some to the RowDetailsViews for Applicants and Jobs, so you can see all the info for an appointment in the dropdown tab view. Otherwise, we're about ready to call a wrap on this oneDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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How about a new platform for your next API… a CMS?

- by Elton Stoneman

Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2014/05/22/how-about-a-new-platform-for-your-next-apihellip-a.aspxSay what? I’m seeing a type of API emerge which serves static or long-lived resources, which are mostly read-only and have a controlled process to update the data that gets served. Think of something like an app configuration API, where you want a central location for changeable settings. You could use this server side to store database connection strings and keep all your instances in sync, or it could be used client side to push changes out to all users (and potentially driving A/B or MVT testing). That’s a good candidate for a RESTful API which makes proper use of HTTP expiration and validation caching to minimise traffic, but really you want a front end UI where you can edit the current config that the API returns and publish your changes. Sound like a Content Mangement System would be a good fit? I’ve been looking at that and it’s a great fit for this scenario. You get a lot of what you need out of the box, the amount of custom code you need to write is minimal, and you get a whole lot of extra stuff from using CMS which is very useful, but probably not something you’d build if you had to put together a quick UI over your API content (like a publish workflow, fine-grained security and an audit trail). You typically use a CMS for HTML resources, but it’s simple to expose JSON instead – or to do content negotiation to support both, so you can open a resource in a browser and see a nice visual representation, or request it with: Accept=application/json and get the same content rendered as JSON for the app to use. Enter Umbraco Umbraco is an open source .NET CMS that’s been around for a while. It has very good adoption, a lively community and a good release cycle. It’s easy to use, has all the functionality you need for a CMS-driven API, and it’s scalable (although you won’t necessarily put much scale on the CMS layer). In the rest of this post, I’ll build out a simple app config API using Umbraco. We’ll define the structure of the configuration resource by creating a new Document Type and setting custom properties; then we’ll build a very simple Razor template to return configuration documents as JSON; then create a resource and see how it looks. And we’ll look at how you could build this into a wider solution. If you want to try this for yourself, it’s ultra easy – there’s an Umbraco image in the Azure Website gallery, so all you need to to is create a new Website, select Umbraco from the image and complete the installation. It will create a SQL Azure website to store all the content, as well as a Website instance for editing and accessing content. They’re standard Azure resources, so you can scale them as you need. The default install creates a starter site for some HTML content, which you can use to learn your way around (or just delete). 1. Create Configuration Document Type In Umbraco you manage content by creating and modifying documents, and every document has a known type, defining what properties it holds. We’ll create a new Document Type to describe some basic config settings. In the Settings section from the left navigation (spanner icon), expand Document Types and Master, hit the ellipsis and select to create a new Document Type: This will base your new type off the Master type, which gives you some existing properties that we’ll use – like the Page Title which will be the resource URL. In the Generic Properties tab for the new Document Type, you set the properties you’ll be able to edit and return for the resource: Here I’ve added a text string where I’ll set a default cache lifespan, an image which I can use for a banner display, and a date which could show the user when the next release is due. This is the sort of thing that sits nicely in an app config API. It’s likely to change during the life of the product, but not very often, so it’s good to have a centralised place where you can make and publish changes easily and safely. It also enables A/B and MVT testing, as you can change the response each client gets based on your set logic, and their apps will behave differently without needing a release. 2. Define the response template Now we’ve defined the structure of the resource (as a document), in Umbraco we can define a C# Razor template to say how that resource gets rendered to the client. If you only want to provide JSON, it’s easy to render the content of the document by building each property in the response (Umbraco uses dynamic objects so you can specify document properties as object properties), or you can support content negotiation with very little effort. Here’s a template to render the document as HTML or JSON depending on the Accept header, using JSON.NET for the API rendering: @inherits Umbraco.Web.Mvc.UmbracoTemplatePage @using Newtonsoft.Json @{ Layout = null; } @if(UmbracoContext.HttpContext.Request.Headers["accept"] != null && UmbracoContext.HttpContext.Request.Headers["accept"] == "application/json") { Response.ContentType = "application/json"; @Html.Raw(JsonConvert.SerializeObject(new { cacheLifespan = CurrentPage.cacheLifespan, bannerImageUrl = CurrentPage.bannerImage, nextReleaseDate = CurrentPage.nextReleaseDate })) } else { <h1>App configuration</h1> <p>Cache lifespan: <b>@CurrentPage.cacheLifespan</b></p> <p>Banner Image: </p> <img src="@CurrentPage.bannerImage"> <p>Next Release Date: <b>@CurrentPage.nextReleaseDate</b></p> } That’s a rough-and ready example of what you can do. You could make it completely generic and just render all the document’s properties as JSON, but having a specific template for each resource gives you control over what gets sent out. And the templates are evaluated at run-time, so if you need to change the output – or extend it, say to add caching response headers – you just edit the template and save, and the next client request gets rendered from the new template. No code to build and ship. 3. Create the content With your document type created, in the Content pane you can create a new instance of that document, where Umbraco gives you a nice UI to input values for the properties we set up on the Document Type: Here I’ve set the cache lifespan to an xs:duration value, uploaded an image for the banner and specified a release date. Each property gets the appropriate input control – text box, file upload and date picker. At the top of the page is the name of the resource – myapp in this example. That specifies the URL for the resource, so if I had a DNS entry pointing to my Umbraco instance, I could access the config with a URL like http://static.x.y.z.com/config/myapp. The setup is all done now, so when we publish this resource it’ll be available to access. 4. Access the resource Now if you open that URL in the browser, you’ll see the HTML version rendered: - complete with the image and formatted date. Umbraco lets you save changes and preview them before publishing, so the HTML view could be a good way of showing editors their changes in a usable view, before they confirm them. If you browse the same URL from a REST client, specifying the Accept=application/json request header, you get this response: That’s the exact same resource, with a managed UI to publish it, being accessed as HTML or JSON with a tiny amount of effort. 5. The wider landscape If you have fairy stable content to expose as an API, I think this approach is really worth considering. Umbraco scales very nicely, but in a typical solution you probably wouldn’t need it to. When you have additional requirements, like logging API access requests - but doing it out-of-band so clients aren’t impacted, you can put a very thin API layer on top of Umbraco, and cache the CMS responses in your API layer: Here the API does a passthrough to CMS, so the CMS still controls the content, but it caches the response. If the response is cached for 1 minute, then Umbraco only needs to handle 1 request per minute (multiplied by the number of API instances), so if you need to support 1000s of request per second, you’re scaling a thin, simple API layer rather than having to scale the more complex CMS infrastructure (including the database). This diagram also shows an approach to logging, by asynchronously publishing a message to a queue (Redis in this case), which can be picked up later and persisted by a different process. Does it work? Beautifully. Using Azure, I spiked the solution above (including the Redis logging framework which I’ll blog about later) in half a day. That included setting up different roles in Umbraco to demonstrate a managed workflow for publishing changes, and a couple of document types representing different resources. Is it maintainable? We have three moving parts, which are all managed resources in Azure – an Azure Website for Umbraco which may need a couple of instances for HA (or may not, depending on how long the content can be cached), a message queue (Redis is in preview in Azure, but you can easily use Service Bus Queues if performance is less of a concern), and the Web Role for the API. Two of the components are off-the-shelf, from open source projects, and the only custom code is the API which is very simple. Does it scale? Pretty nicely. With a single Umbraco instance running as an Azure Website, and with 4x instances for my API layer (Standard sized Web Roles), I got just under 4,000 requests per second served reliably, with a Worker Role in the background saving the access logs. So we had a nice UI to publish app config changes, with a friendly Web preview and a publishing workflow, capable of supporting 14 million requests in an hour, with less than a day’s effort. Worth considering if you’re publishing long-lived resources through your API.

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Creating a JSONP Formatter for ASP.NET Web API

- by Rick Strahl

Out of the box ASP.NET WebAPI does not include a JSONP formatter, but it's actually very easy to create a custom formatter that implements this functionality. JSONP is one way to allow Browser based JavaScript client applications to bypass cross-site scripting limitations and serve data from the non-current Web server. AJAX in Web Applications uses the XmlHttp object which by default doesn't allow access to remote domains. There are number of ways around this limitation <script> tag loading and JSONP is one of the easiest and semi-official ways that you can do this. JSONP works by combining JSON data and wrapping it into a function call that is executed when the JSONP data is returned. If you use a tool like jQUery it's extremely easy to access JSONP content. Imagine that you have a URL like this: http://RemoteDomain/aspnetWebApi/albums which on an HTTP GET serves some data - in this case an array of record albums. This URL is always directly accessible from an AJAX request if the URL is on the same domain as the parent request. However, if that URL lives on a separate server it won't be easily accessible to an AJAX request. Now, if the server can serve up JSONP this data can be accessed cross domain from a browser client. Using jQuery it's really easy to retrieve the same data with JSONP:function getAlbums() { $.getJSON("http://remotedomain/aspnetWebApi/albums?callback=?",null, function (albums) { alert(albums.length); }); } The resulting callback the same as if the call was to a local server when the data is returned. jQuery deserializes the data and feeds it into the method. Here the array is received and I simply echo back the number of items returned. From here your app is ready to use the data as needed. This all works fine - as long as the server can serve the data with JSONP. What does JSONP look like? JSONP is a pretty simple 'protocol'. All it does is wrap a JSON response with a JavaScript function call. The above result from the JSONP call looks like this:Query17103401925975181569_1333408916499( [{"Id":"34043957","AlbumName":"Dirty Deeds Done Dirt Cheap",…},{…}] ) The way JSONP works is that the client (jQuery in this case) sends of the request, receives the response and evals it. The eval basically executes the function and deserializes the JSON inside of the function. It's actually a little more complex for the framework that does this, but that's the gist of what happens. JSONP works by executing the code that gets returned from the JSONP call. JSONP and ASP.NET Web API As mentioned previously, JSONP support is not natively in the box with ASP.NET Web API. But it's pretty easy to create and plug-in a custom formatter that provides this functionality. The following code is based on Christian Weyers example but has been updated to the latest Web API CodePlex bits, which changes the implementation a bit due to the way dependent objects are exposed differently in the latest builds. Here's the code: using System; using System.IO; using System.Net; using System.Net.Http.Formatting; using System.Net.Http.Headers; using System.Threading.Tasks; using System.Web; using System.Net.Http; namespace Westwind.Web.WebApi { /// <summary> /// Handles JsonP requests when requests are fired with /// text/javascript or application/json and contain /// a callback= (configurable) query string parameter /// /// Based on Christian Weyers implementation /// https://github.com/thinktecture/Thinktecture.Web.Http/blob/master/Thinktecture.Web.Http/Formatters/JsonpFormatter.cs /// </summary> public class JsonpFormatter : JsonMediaTypeFormatter { public JsonpFormatter() { SupportedMediaTypes.Add(new MediaTypeHeaderValue("application/json")); SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/javascript")); //MediaTypeMappings.Add(new UriPathExtensionMapping("jsonp", "application/json")); JsonpParameterName = "callback"; } /// <summary> /// Name of the query string parameter to look for /// the jsonp function name /// </summary> public string JsonpParameterName {get; set; } /// <summary> /// Captured name of the Jsonp function that the JSON call /// is wrapped in. Set in GetPerRequestFormatter Instance /// </summary> private string JsonpCallbackFunction; public override bool CanWriteType(Type type) { return true; } /// <summary> /// Override this method to capture the Request object /// and look for the query string parameter and /// create a new instance of this formatter. /// /// This is the only place in a formatter where the /// Request object is available. /// </summary> /// <param name="type"></param> /// <param name="request"></param> /// <param name="mediaType"></param> /// <returns></returns> public override MediaTypeFormatter GetPerRequestFormatterInstance(Type type, HttpRequestMessage request, MediaTypeHeaderValue mediaType) { var formatter = new JsonpFormatter() { JsonpCallbackFunction = GetJsonCallbackFunction(request) }; return formatter; } /// <summary> /// Override to wrap existing JSON result with the /// JSONP function call /// </summary> /// <param name="type"></param> /// <param name="value"></param> /// <param name="stream"></param> /// <param name="contentHeaders"></param> /// <param name="transportContext"></param> /// <returns></returns> public override Task WriteToStreamAsync(Type type, object value, Stream stream, HttpContentHeaders contentHeaders, TransportContext transportContext) { if (!string.IsNullOrEmpty(JsonpCallbackFunction)) { return Task.Factory.StartNew(() => { var writer = new StreamWriter(stream); writer.Write( JsonpCallbackFunction + "("); writer.Flush(); base.WriteToStreamAsync(type, value, stream, contentHeaders, transportContext).Wait(); writer.Write(")"); writer.Flush(); }); } else { return base.WriteToStreamAsync(type, value, stream, contentHeaders, transportContext); } } /// <summary> /// Retrieves the Jsonp Callback function /// from the query string /// </summary> /// <returns></returns> private string GetJsonCallbackFunction(HttpRequestMessage request) { if (request.Method != HttpMethod.Get) return null; var query = HttpUtility.ParseQueryString(request.RequestUri.Query); var queryVal = query[this.JsonpParameterName]; if (string.IsNullOrEmpty(queryVal)) return null; return queryVal; } } } Note again that this code will not work with the Beta bits of Web API - it works only with post beta bits from CodePlex and hopefully this will continue to work until RTM :-) This code is a bit different from Christians original code as the API has changed. The biggest change is that the Read/Write functions no longer receive a global context object that gives access to the Request and Response objects as the older bits did. Instead you now have to override the GetPerRequestFormatterInstance() method, which receives the Request as a parameter. You can capture the Request there, or use the request to pick up the values you need and store them on the formatter. Note that I also have to create a new instance of the formatter since I'm storing request specific state on the instance (information whether the callback= querystring is present) so I return a new instance of this formatter. Other than that the code should be straight forward: The code basically writes out the function pre- and post-amble and the defers to the base stream to retrieve the JSON to wrap the function call into. The code uses the Async APIs to write this data out (this will take some getting used to seeing all over the place for me). Hooking up the JsonpFormatter Once you've created a formatter, it has to be added to the request processing sequence by adding it to the formatter collection. Web API is configured via the static GlobalConfiguration object. protected void Application_Start(object sender, EventArgs e) { // Verb Routing RouteTable.Routes.MapHttpRoute( name: "AlbumsVerbs", routeTemplate: "albums/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumApi" } ); GlobalConfiguration .Configuration .Formatters .Insert(0, new Westwind.Web.WebApi.JsonpFormatter()); } That's all it takes. Note that I added the formatter at the top of the list of formatters, rather than adding it to the end which is required. The JSONP formatter needs to fire before any other JSON formatter since it relies on the JSON formatter to encode the actual JSON data. If you reverse the order the JSONP output never shows up. So, in general when adding new formatters also try to be aware of the order of the formatters as they are added. Resources JsonpFormatter Code on GitHub© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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