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  • What is the fastest way to get a DataTable into SQL Server?

    - by John Gietzen
    I have a DataTable in memory that I need to dump straight into a SQL Server temp table. After the data has been inserted, I transform it a little bit, and then insert a subset of those records into a permanent table. The most time consuming part of this operation is getting the data into the temp table. Now, I have to use temp tables, because more than one copy of this app is running at once, and I need a layer of isolation until the actual insert into the permanent table happens. What is the fastest way to do a bulk insert from a C# DataTable into a SQL Temp Table? I can't use any 3rd party tools for this, since I am transforming the data in memory. My current method is to create a parameterized SqlCommand: INSERT INTO #table (col1, col2, ... col200) VALUES (@col1, @col2, ... @col200) and then for each row, clear and set the parameters and execute. There has to be a more efficient way. I'm able to read and write the records on disk in a matter of seconds...

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  • Problems with Database Search Code (asp.net vb)

    - by Phil
    Here is a sample of my database search code: Dim sql As String = "Select * From Table Where " Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim andor As Boolean = AndOr1.SelectedValue 'selection can be AND or OR (0 / 1) 'Code for when the user selects AND If NameSearch.Text.ToString IsNot String.Empty And andor = 0 Then sql += "Surname LIKE '%" & name & "%' AND " End If If EmailSearch.Text.ToString IsNot String.Empty And andor = 0 Then sql += "Email LIKE '%" & email & "%' AND " End If If CitySearchBox.Text.ToString IsNot String.Empty And andor = 0 Then sql += "City LIKE '%" & city & "%' AND " End If 'Code for when the user selects OR If NameSearch.Text.ToString IsNot String.Empty And andor = 1 Then sql += "(Surname LIKE '%" & name & "%' OR " End If If EmailSearch.Text.ToString IsNot String.Empty And andor = 1 Then sql += "Email LIKE '%" & email & "%') OR " End If If CitySearchBox.Text.ToString IsNot String.Empty And andor = 1 Then sql += "(City LIKE '%" & city & "%' OR " End If sql = CleanString(sql) End Sub When the user selects AND (as andor.selectedvalue(0)) then the sql is produced fine like this; Select * From Table Where Surname LIKE '%test%' AND Email LIKE '%test%' AND City LIKE '%test%' But if the user selects OR (as andor.selectedvalue(1)), nothing is outputted except; Select * From Table Where Im sure the controls have values so are not string.empty and when the user selects OR the correct value 1 is being assigned to andor.

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  • How to make BoxLayout vertical but children flow top-aligned?

    - by user291701
    I'm trying to get get a vertical, top-aligned layout to work. This is what I have: JPanel pane = new JPanel(); pane.setLayout(new BoxLayout(pane, BoxLayout.Y_AXIS)); MyImagePanel panelImage = new MyImagePanel(); panelImage.setSize(400, 400); pane.add(new JComboBox()); pane.add(panelImage); pane.add(new JButton("1")); pane.add(new JButton("2")); pane.add(new JButton("3")); JFrame frame = new JFrame("Title"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(800, 600); frame.add(pane); frame.pack(); frame.setVisible(true); All the controls appear, but it looks like padding is being applied at run time between their tops and bottoms so they're somewhat vertically centered. This is what I'm going for: ----------------------------------------------------- | ComboBox | | ------------ | | | | | Image | | | | | ------------ | | Button 1 | Any additional space fills the right | ------------ | | Button 2 | | ------------ | | Button 3 | | ------------ | | | | Any additional space fills the bottom | | | ----------------------------------------------------- How do I get BoxLayout to do that? Thanks ------------------------- Update ------------------------- Was able to use this: Box vertical = Box.createVerticalBox(); frame.add(vertical, BorderLayout.NORTH); vertical.add(new JComboBox()); vertical.add(new JButton("1")); ... to get what I wanted.

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  • Uniform grid Rows and Columns

    - by Carlo
    I'm trying to make a grid based on a UniformGrid to show the coordinates of each cell, and I want to show the values on the X and Y axes like so: _A_ _B_ _C_ _D_ 1 |___|___|___|___| 2 |___|___|___|___| 3 |___|___|___|___| 4 |___|___|___|___| Anyway, in order to do that I need to know the number of columns and rows in the Uniform grid, and I tried overriding the 3 most basic methods where the arrangement / drawing happens, but the columns and rows in there are 0, even though I have some controls in my grid. What method can I override so my Cartesian grid knows how many columns and rows it has? C#: public class CartesianGrid : UniformGrid { protected override Size MeasureOverride(Size constraint) { Size size = base.MeasureOverride(constraint); int computedColumns = this.Columns; // always 0 int computedRows = this.Rows; // always 0 return size; } protected override Size ArrangeOverride(Size arrangeSize) { Size size = base.ArrangeOverride(arrangeSize); int computedColumns = this.Columns; // always 0 int computedRows = this.Rows; // always 0 return size; } protected override void OnRender(DrawingContext dc) { int computedColumns = this.Columns; // always 0 int computedRows = this.Rows; // always 0 base.OnRender(dc); } } XAML: <local:CartesianGrid> <Label Content="Hello" /> <Label Content="Hello" /> <Label Content="Hello" /> <Label Content="Hello" /> <Label Content="Hello" /> <Label Content="Hello" /> </local:CartesianGrid> Any help is greatly appreciated. Thanks!

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  • Suffix if statement

    - by Aardschok
    I was looking for a way to add a suffix to jointchain in Maya. The jointchain has specific naming so I create a list with the names they need to be. The first chain has "_1" as suffix, result: R_Clavicle_1|R_UpperArm_1|R_UnderArm_1|R_Wrist_1 When I create the second this is the result: R_Clavicle_2|R_UpperArm_1|R_UnderArm_1|R_Wrist_1 The code: DRClavPos = cmds.xform ('DRClavicle', q=True, ws=True, t=True) DRUpArmPos = cmds.xform ('DRUpperArm', q=True, ws=True, t=True) DRUnArmPos = cmds.xform ('DRUnderArm', q=True, ws=True, t=True) DRWristPos = cmds.xform ('DRWrist', q=True, ws=True, t=True), cmds.xform('DRWrist', q=True, os=True, ro=True) suffix = 1 jntsA = cmds.ls(type="joint", long=True) while True: jntname = ["R_Clavicle_"+str(suffix),"R_UpperArm_"+str(suffix),"R_UnderArm_"+str(suffix),"R_Wrist_"+str(suffix)] if jntname not in jntsA: cmds.select (d=True) cmds.joint ( p=(DRClavPos)) cmds.joint ( p=(DRUpArmPos)) cmds.joint ( 'joint1', e=True, zso=True, oj='xyz', radius=0.5, n=jntname[0]) cmds.joint ( p=(DRUnArmPos)) cmds.joint ( 'joint2', e=True, zso=True, oj='xyz', radius=0.5, n=jntname[1]) cmds.joint ( p=(DRWristPos[0])) cmds.joint ( 'joint3', e=True, zso=True, oj='xyz', radius=0.5, n=jntname[2]) cmds.rename ('joint4', jntname[3]) cmds.select ( cl=True) break else: suffix + 1 I tried adding +1 in jntname which resulted in a good second chain but the third chain had "_2" after R_Clavicle_3 The code, in my eyes should work. Can anybody point me in the correct direction :)

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  • How to Prevent PostBack Event Handler from Firing

    - by user331744
    I have a custom class (ServerSideValidator.vb) that validates user input on server side (it doesn't use any of the .NET built in validators, therefore Page.Validate() is not an option for me). I am calling the Validate() method on page.IsPostback event and the class performs without any problem My issue is, when validation fails (returns false), I want to stop the postback event handler from firing, but load the page along with all the controls and user-input values in them. If I do, Response.End(), the page comes up blank. I can programmatically instruct the page to go to the previous page (original form before postback), but it loses all user-inputs. I thought of creating a global boolean variable in the page code behind file and check the value before performing any postback method, but this approach takes away from my plan to provide all functionalities inside the class itself. The page object is being referenced to ServerSideValidator. Seems like all the postback related properties/variables I come across inside Page class are 'Readonly' and I can't assign value(s) to control/prevent postback event from firing. Any idiea on how I can accomplish this? Please let me know if you need further details

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  • Software usage analytics in C#

    - by TiernanO
    I have a project i am working on currently and would like to implement some sort of software tracking in the code. ideally, stuff like how often its launched. how long it runs for, feature tracking, etc. I already use Exceptioneer for unhandled exceptions, but would like something similar for usage tracking. this data should all be anonymous and ideally run as a service by someone else. and i would like to give the users the option to turn it off, if they so wish to... So, is this something i should implement myself, or are there third parties out there that do this sort of things? i know it might be a sticky area, but i have seen stats about iPhone app usage. they do it, so why cant we? (if the user agrees, of course) [Update] Based on the comments, i should have been more clear. this is a Winforms .NET 4. application, though i am thinking of updating it later with WCF. i would only be tracking my own application, though i would also want to know minor information about environment (Windows OS Version, SP, maybe proc and ram...)

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  • RMagick transparent_color deprecated? What's the alternative?

    - by user315975
    I'm developing an app that does a fair amount of generating transparent pngs on the fly. These are used as overlays, to show areas of interest in a graphic, so they have to have transparent backgrounds. I am developing in Ruby on Rails, deploying on Heroku. What works fine in development is not working in production. I get this error when I call a drawing routine using RMagick: NotImplementedError (the `transparent_color=' method is not supported by ImageMagick 6.2.4): /usr/local/lib/ruby/gems/1.8/gems/rmagick-1.15.17/lib/RMagick.rb:1691:in `transparent_color=' I'm using RMagick version 2.12.1 on the development machine, but I'm not exactly certain how to discover the version of ImageMagick that it's running, so I'm not sure if this is a case of my local code being behind or ahead. I'm hoping behind, because perhaps then there'll be a replacement for this call. Does anyone know what the fix is here? What's required to generate a transparent background, if not the call I'm using? I can't find this in the documentation: in fact, it was on a third-party site that I found mention of this capability.

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  • Creating Modules for VB Program (Similar to firefox add on)

    - by Assimilater
    Hi all. I have a contact manager program that I'd like to design for multiple network marketing companies. My desired structure would include a core program which covers basic contact management functions. After that one could purchase a module for their specific network marketing company. This module would contain a variety of controls that the original program would need to be able to manipulate. Here is an example of what it would have to have: A group box containing buttons that link to a genealogy view, and the option to import one's donwnline from the back office provided by a company. A panel which is displayed on the contact page allowing the user to input business information or which will be filled by importing a downline from the back office: ie business ID, qualification level, sponsor information etc. a panel displayed when one searches for contacts on the contact list page which allows the user to sort based on information such as when they joined, what their business id is and so forth. a panel which is displayed in a personal business overview page which presents to an individual how many people in their downline are at each qualification level and develop a mailing list for individuals of a certain qualification level. I have the code developed to perform all these functions, I just wanted to give you an example of what needed to be done. I'm thinking that what I'm trying to create is a library that one can download and the program will recognize, but I'm not really sure where to go. What I'm really trying to do is figure out what kind of file I can make that will contain all this code and the GUI information that the program will recognize. Any ideas? With thanks, John

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  • Why is CoRegisterClassObject creating two extra threads?

    - by Stijn Sanders
    I'm trying to fix a problem that only recently happens on a number of machine's on a VPN. They each run a client application I wrote that exposes a COM automation object. For some strange reason I haven't been able to discover yet, one thread in the application takes up all of the available CPU time, slowing other operation on the machine. In observing the application's strange behaviour, I've noticed it's the third thread started, and if I debug on my machine I notice the first call to CoRegisterClassObject created two extra threads. If the second of these two threads is the one that gets into an infinite loop, I'm not at all shure how to fix this. Where could I check next about what's wrong? Could it have started by one of the recent patches rolled out by Microsoft this last 'patch tuesday'? I had a go with ProcessExplorer to extract a stack trace of the thread: ntoskrnl.exe!ExReleaseResourceLite+0x1a3 ntoskrnl.exe!PsGetContextThread+0x329 WLDAP32.dll!Ordinal325+0x1231 WLDAP32.dll!Ordinal325+0x129e WLDAP32.dll!Ordinal325+0x1178 ntdll.dll!LdrInitializeThunk+0x24 ntdll.dll!LdrShutdownThread+0xe9 kernel32.dll!ExitThread+0x3e kernel32.dll!FreeLibraryAndExitThread+0x1e ole32.dll!StringFromGUID2+0x65d kernel32.dll!GetModuleFileNameA+0x1ba

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  • Drupal module for complex hours of operation / office hours

    - by Eronarn
    Background: I am building a website in Drupal that links together a wide variety of social service providers for the purposes of discovery, collaboration, and all that good stuff. The goal is to make a website that is simple to browse for consumers of these services and simple to update for providers of these services. The beta has been very well received, but I want to switch to a different information schema before the site goes live. Specific question: I am looking for a module (or other solution) that... Stores this data in Drupal (i.e., no GCal) Supports a wide variety of repeats Is intuitive for people editing the node (no Cron-style interfaces, please!) I have looked into several modules on drupal.org and none seem to meet all of these criteria. I've also searched here, and while this question is similar: http://stackoverflow.com/questions/2794149/drupal-create-a-node-with-employee-working-hours my needs are too complex for the offered solution. Some of these providers have "hours" such as "the third Wednesday of every month", or "open during Winter months", or separate hotline & office hours. Likewise, the Date Repeat module doesn't cut it as stands currently. I'm comfortable hacking what I need into an existing module - I just don't want to duplicate effort! If you have a suggestion on what module might be a good starting point, I'd appreciate that input, too. Thanks. <3

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  • Using DisplayFor inside a display template

    - by Oenotria
    I've created a htmlhelper extension to reduce the amount of repetitive markup when creating forms: public static MvcHtmlString RenderField<TModel, TValue>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TValue>> expression) { return htmlHelper.DisplayFor(expression, "formfield"); } The idea being that inside my views I can just write @Html.RenderField(x=>x.MyFieldName) and it will print the label and the field's content with the appropriate div tags in place already. Inside the displaytemplates folder I have created formfield.cshtml containing the following: <div class="display-group"> <div class="display-label"> @Html.LabelFor(x => x) </div> <div class="display-field"> @Html.DisplayFor(x => x) </div> </div> Unfortunately it doesn't appear that it is possible to nest DisplayFor inside a display template (it doesn't render anything). I don't want to just using @Model because then I won't get checkboxes for boolean values, calendar controls for dates etc. Is there a good way around this?

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  • Problem with derived ControlTemplates in WPF

    - by Frank Fella
    The following xaml code works: <Window x:Class="DerivedTemplateBug.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:DerivedTemplateBug" Title="Window1" Height="300" Width="300"> <Button> <Button.Template> <ControlTemplate> <Border BorderBrush="Black" BorderThickness="2"> <TextBlock>Testing!</TextBlock> </Border> </ControlTemplate> </Button.Template> </Button> </Window> Now, if you define the following data template: using System.Windows.Controls; namespace DerivedTemplateBug { public class DerivedTemplate : ControlTemplate { } } And then swap the ControlTemplate for the derived class: <Window x:Class="DerivedTemplateBug.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:DerivedTemplateBug" Title="Window1" Height="300" Width="300"> <Button> <Button.Template> <local:DerivedTemplate> <Border BorderBrush="Black" BorderThickness="2"> <TextBlock>Testing!</TextBlock> </Border> </local:DerivedTemplate> </Button.Template> </Button> </Window> You get the following error: Invalid ContentPropertyAttribute on type 'DerivedTemplateBug.DerivedTemplate', property 'Content' not found. Can anyone tell me why this is the case?

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  • How to Bind a Command in WPF

    - by MegaMind
    Sometimes we used complex ways so many times, we forgot the simplest ways to do the task. I know how to do command binding, but i always use same approach. Create a class that implements ICommand interface and from the view model i create new instance of that class and binding works like a charm. This is the code that i used for command binding public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); DataContext = this; testCommand = new MeCommand(processor); } ICommand testCommand; public ICommand test { get { return testCommand; } } public void processor() { MessageBox.Show("hello world"); } } public class MeCommand : ICommand { public delegate void ExecuteMethod(); private ExecuteMethod meth; public MeCommand(ExecuteMethod exec) { meth = exec; } public bool CanExecute(object parameter) { return false; } public event EventHandler CanExecuteChanged; public void Execute(object parameter) { meth(); } } But i want to know the basic way to do this, no third party dll no new class creation. Do this simple command binding using a single class. Actual class implements from ICommand interface and do the work.

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  • Garbage data from serial port.

    - by sasayins
    Hi I wrote a code in Linux platform that read the data in serial port, my code below: int fd; char *rbuff=NULL; struct termios new_opt, old_opt; int ret; fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY); if( fd == -1 ) { printf("Can't open file: %s\n", strerror(errno)); return -1; } tcgetattr(fd, &old_opt); new_opt.c_cflag = B115200 | CS8 | CLOCAL | CREAD; new_opt.c_iflag = IGNPAR /*| ICRNL*/; new_opt.c_oflag = 0; new_opt.c_lflag = ICANON; tcsetattr(fd, TCSANOW, &new_opt); rbuff = malloc(NBUFF); printf("reading..\n"); memset(rbuff,0x00,NBUFF); ret = read(fd, rbuff, NBUFF); printf("value:%s",rbuff); if(ret == -1) { printf("Read error:%s\n",strerror(errno)); return -1; } tcsetattr(fd, TCSANOW, &old_opt); close(fd); My problem is the code above doesn't read the first data that was transmitted, then the second transmission the data is garbage, then the third is the normal data. Did I missed a setting in the serial port? Thanks.

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  • What's the most trivial function that would benfit from being computed on a GPU?

    - by hanDerPeder
    Hi. I'm just starting out learning OpenCL. I'm trying to get a feel for what performance gains to expect when moving functions/algorithms to the GPU. The most basic kernel given in most tutorials is a kernel that takes two arrays of numbers and sums the value at the corresponding indexes and adds them to a third array, like so: __kernel void add(__global float *a, __global float *b, __global float *answer) { int gid = get_global_id(0); answer[gid] = a[gid] + b[gid]; } __kernel void sub(__global float* n, __global float* answer) { int gid = get_global_id(0); answer[gid] = n[gid] - 2; } __kernel void ranksort(__global const float *a, __global float *answer) { int gid = get_global_id(0); int gSize = get_global_size(0); int x = 0; for(int i = 0; i < gSize; i++){ if(a[gid] > a[i]) x++; } answer[x] = a[gid]; } I am assuming that you could never justify computing this on the GPU, the memory transfer would out weight the time it would take computing this on the CPU by magnitudes (I might be wrong about this, hence this question). What I am wondering is what would be the most trivial example where you would expect significant speedup when using a OpenCL kernel instead of the CPU?

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  • WCF: collection proxy type on client

    - by Unholy
    I have the following type in wsdl (it is generated by third party tool): <xsd:complexType name="IntArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:int" /> </xsd:sequence> </xsd:complexType> Sometimes Visual Studio generates: public class IntArray : System.Collections.Generic.List<int> {} And sometimes it doesn't generate any proxy type for this wsdl and just uses int[]. Collection type in Web Service configuration is System.Array. What could be the reason for such upredictable behavior? Edited: I found the way how I can reproduce this behavior. For examle we have two types: <xsd:complexType name="IntArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:int" /> </xsd:sequence> </xsd:complexType> <xsd:complexType name="StringArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:string" /> </xsd:sequence> </xsd:complexType> VS generates: public class IntArray : System.Collections.Generic.List<int> {} public class StringArray : System.Collections.Generic.List<string> {} Now I change StringArray type: <xsd:complexType name="StringArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:string" /> <xsd:any minOccurs="0" maxOccurs="unbounded" namespace="##any" processContents="lax" /> </xsd:sequence> <xsd:anyAttribute namespace="##any" processContents="lax"/> </xsd:complexType> VS generates proxy type for StringArray only. But not for IntArray.

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  • What wrapper class in C++ should I use for automated resource management?

    - by Vilx-
    I'm a C++ amateur. I'm writing some Win32 API code and there are handles and weirdly compositely allocated objects aplenty. So I was wondering - is there some wrapper class that would make resource management easier? For example, when I want to load some data I open a file with CreateFile() and get a HANDLE. When I'm done with it, I should call CloseHandle() on it. But for any reasonably complex loading function there will be dozens of possible exit points, not to mention exceptions. So it would be great if I could wrap the handle in some kind of wrapper class which would automatically call CloseHandle() once execution left the scope. Even better - it could do some reference counting so I can pass it around in and out of other functions, and it would release the resource only when the last reference left scope. The concept is simple - but is there something like that in the standard library? I'm using Visual Studio 2008, by the way, and I don't want to attach a 3rd party framework like Boost or something.

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  • Binding a value to one of two possibilities in Guice

    - by Kelvin Chung
    Suppose I have a value for which I have a default, which can be overridden if System.getProperty("foo") is set. I have one module for which I have bindConstant().annotatedWith(Names.named("Default foo")).to(defaultValue); I'm wondering what the best way of implementing a module for which I want to bind something annotated with "foo" to System.getProperty("foo"), or, if it does not exist, the "Default foo" binding. I've thought of a simple module like so: public class SimpleIfBlockModule extends AbstractModule { @Override public void configure() { requireBinding(Key.get(String.class, Names.named("Default foo"))); if (System.getProperties().containsKey("foo")) { bindConstant().annotatedWith(Names.named("foo")).to(System.getProperty("foo")); } else { bind(String.class).annotatedWith(Names.named("foo")).to(Key.get(String.class, Names.named("Default foo"))); } } } I've also considered creating a "system property module" like so: public class SystemPropertyModule extends PrivateModule { @Override public void configure() { Names.bindProperties(binder(), System.getProperties()); if (System.getProperties().contains("foo")) { expose(String.class).annotatedWith(Names.named("foo")); } } } And using SystemPropertyModule to create an injector that a third module, which does the binding of "foo". Both of these seem to have their downsides, so I'm wondering if there is anything I should be doing differently. I was hoping for something that's both injector-free and reasonably generalizable to multiple "foo" attributes. Any ideas?

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  • what is the best practice approach for n-tier application development with entity framework?

    - by samsur
    I am building an application using entity framework. I am using the T4 template to generate self tracking entities. Currently, I am thinking of creating the entity framework code in a separate project. In this same project, I would have partial classes with additional methods for the entities. I am thinking of creating a separate project for a service layer (WCF) with methods for the upper/presentation tier. The WCF layer will reference the entity framework project. The methods in the WCF layer will return the entities or accept the entities as the parameters. I am thinkg of creating a third project for the presentation layer (ASP.net), this will make calls to the WCF service but will also need to reference the entities as the WCF methods take these types as the parameters/return types. In short, i want to use the STE entities generated by the T4 template as a DTO to be used in all layers. I was originally thinking of creating a business logic layer that maps to each entities. Example: If i have a customer class, the Business Layer would have a CustomerBLL class and then methods in the customerBLL will be used by the service layer. I was also trying to create a DTO in this business layer. I however found that this approach is very time consuming and i do not see a major benefit as it would create more maintenance work. What is the best practice for n-tier application development using entity framework 4?

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  • How to limit TCP writes to particular size and then block untlil the data is read

    - by ustulation
    {Qt 4.7.0 , VS 2010} I have a Server written in Qt and a 3rd party client executable. Qt based server uses QTcpServer and QTcpSocket facilities (non-blocking). Going through the articles on TCP I understand the following: the original implementation of TCP mentioned the negotiable window size to be a 16-bit value, thus maximum being 65535 bytes. But implementations often used the RFC window-scale-extension that allows the sliding window size to be scalable by bit-shifting to yield a maximum of 1 gigabyte. This is implementation defined. This could have resulted in majorly different window sizes on receiver and sender end as the server uses Qt facilities without hardcoding any window size limit. Client 1st asks for all information it can based on the previous messages from the server before handling the new (accumulating) incoming messages. So at some point Server receives a lot of messages each asking for data of several MB's. This the server processes and puts it into the sender buffer. Client however is unable to handle the messages at the same pace and it seems that client’s receiver buffer is far smaller (65535 bytes maybe) than sender’s transmit window size. The messages thus get accumulated at sender’s end until the sender’s buffer is full too after which the TCP writes on sender would block. This however does not happen as sender buffer is much larger. Hence this manifests as increase in memory consumption on the sender’s end. To prevent this from happening, I used Qt’s socket’s waitForBytesWritten() with timeout set to -1 for infinite waiting period. This as I see from the behaviour blocks the thread writing TCP data until the data has actually been sensed by the receiver’s window (which will happen when earlier messages have been processed by the client at application level). This has caused memory consumption at Server end to be almost negligible. is there a better alternative to this (in Qt) if i want to restrict the memory consumption at server end to say x MB's? Also please point out if any of my understandings is incorrect.

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  • C++ MFC server app with sockets crashes and I cannot find the fault, help!

    - by usermeister
    My program has one dialog and two sockets. Both sockets are derived from CAsyncSocket, one is for listening, other is for receiving data from client. My program crashes when client tries to connect to server application and server needs to initialize receiving socket. This is my MFC dialog class. class CFileTransferServerDlg : public CDialog { ... ListeningSocket ListenSock; ReceivingSocket* RecvSock; void OnAccept(); // called when ListenSock gets connection attempt ... }; This is my derived socket class for receiving data that calls parent dialogs method when event is signaled. class ReceivingSocket : public CAsyncSocket { CFileTransferServerDlg* m_pDlg; // for accessing parent dialogs controls virtual void OnReceive(int nErrorCode); } ReceivingSocket::ReceivingSocket() { } This is dialogs function that handles incoming connection attempt when listening socket gets event notification. This is where the crash happens. void CFileTransferServerDlg::OnAccept() { RecvSock = new ReceivingSocket; /* CRASH */ } OR void CFileTransferServerDlg::OnAccept() { ReceivingSocket* tmpSock = new ReceivingSocket; tmpSock->SetParentDlg(this); CString message; if( ListenSock.Accept(*tmpSock) ) /* CRASH */ { message.LoadStringW(IDS_CLIENT_CONNECTED); m_txtStatus.SetWindowTextW(message); RecvSock = tmpSock; } } My program crashes when I try to create a socket for receiving file sent from client application. OnAccept starts when Listening socket signals incoming connection attempt, but my application then crashes. I've tried running it on another computer and connection attempt was succesful. What could be wrong? Error in debug mode: Unhandled exception at 0x009c30e1 in FileTransferServer.exe: 0xC0000005: Access violation reading location 0xccccce58.

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  • MATLAB: svds() not converging

    - by Paul
    So using MATLAB's svds() function on some input data as such: [U, S, V, flag] = svds(data, nSVDs, 'L') I noticed that from run to run with the same data, I'd get drastically different output SVD sizes from run to run. When I checked whether 'flag' was set, I found that it was, indicating that the SVDs had not converged. My normal system here would be that if it really needs to converge, I'd do something like this: flag = 1 svdOpts = struct('tol', 1e-10, 'maxit', 600, 'disp', 0); while flag: if svdOpts.maxit > 1e6 error('There''s a real problem here.') end [U, S, V, flag] = svds(data, nSVDs, 'L', svdOpts) svdOpts.maxit = svdOpts.maxit*2 end But from what I can tell, when you use 'L' as the third argument, the fourth argument is ignored, meaning I just have to deal with the fact that it's not converging? I'm not even really sure how to use the 'sigma' argument in place of the 'L' argument. I've also tried reducing the number of SVDs calculated to no avail. Any help on this matter would be much appreciated. EDIT While following up on the comments below, I found that the problem had to do with the way I was building my data matrices. Turned out I had accidentally inverted a matrix and had an input of size (4000x1) rather than (20x200), which was what was refusing to converge. I also did some more timing tets and found that the fourth argument was not, in fact, being ignored, so that's on me. Thanks for the help guys.

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  • Flex 3 (Action Script): How to access a function from a loaded swf-file ?

    - by Trantec
    Hi, i load in ActionScript a swf file. So far no Problem, but I didn't found a way to access one of it's functions, the best thing would be if I could access the main function in the mxml part of the swf. Here is the code of the main-mxml file that belongs to the swf that should load and access another swf: <?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="basket();"> <mx:Script> <![CDATA[ import mx.controls.SWFLoader; private function basket(): void { var swfLoader: SWFLoader = new SWFLoader(); swfLoader.addEventListener( Event.COMPLETE, handleSWFLoaded ); try { swfLoader.load( "../../data/InternalSWF.swf" ); } catch (error: Error) { trace( "Couldn't load file !" ); } } private function handleSWFLoaded( event: Event ): void { var swfApp:* = event.target.content; // This both ways don't work... //if (swfApp.hasOwnProperty("initApp")) { // var initApp:Function = (swfApp["initApp"] as Function); // initApp(); //} // swfApp.initApp(); } ]]> </mx:Script> <mx:Text id="output" width="100%" textAlign="center" /> </mx:Application> The if-Statement "if (swfApp.hasOwnProperty("initApp")) {" is never true and the call "swfApp.initApp()" says that this function does not exist. In the original version I added event listeners for HTTPStatusEvent.HTTP_STATUS, IOErrorEvent.IO_ERROR and SecurityErrorEvent.SECURITY_ERROR. But except for HTTP_STATUS = 0 none of them are called. Is the whole idea of how i try to do this wrong ?

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  • Performing centralized authorization for multiple applications

    - by Vaibhav
    Here's a question that I have been wrestling with for a while. We have a situation wherein we have a number of applications that we have created. These have grown organically over a period of time. All of these applications have permissions code built into them that controls access to various parts of the application depending on whether the currently logged in user has the necessary permissions or not. Alongside these applications is a utility application which allows an administrator to map users to permissions for all applications - the way it works is that every application has code which reads this external database of the said utility application to check if the currently logged in user has the necessary permission or not. Now, the question is this. Should the user-permissions mapping information reside in and be owned by the applications themselves, or is it okay to have this information reside within an external entity/DB (as in this case the utility application's database). Part of me thinks that application permissions are very specific to the application context itself, so shouldn't be separated from the application itself. But I am not sure. Any comments?

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