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Articles indexed Sunday March 18 2012

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  • Dynamic Types and DynamicObject References in C#

    - by Rick Strahl
    I've been working a bit with C# custom dynamic types for several customers recently and I've seen some confusion in understanding how dynamic types are referenced. This discussion specifically centers around types that implement IDynamicMetaObjectProvider or subclass from DynamicObject as opposed to arbitrary type casts of standard .NET types. IDynamicMetaObjectProvider types  are treated special when they are cast to the dynamic type. Assume for a second that I've created my own implementation of a custom dynamic type called DynamicFoo which is about as simple of a dynamic class that I can think of:public class DynamicFoo : DynamicObject { Dictionary<string, object> properties = new Dictionary<string, object>(); public string Bar { get; set; } public DateTime Entered { get; set; } public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; if (!properties.ContainsKey(binder.Name)) return false; result = properties[binder.Name]; return true; } public override bool TrySetMember(SetMemberBinder binder, object value) { properties[binder.Name] = value; return true; } } This class has an internal dictionary member and I'm exposing this dictionary member through a dynamic by implementing DynamicObject. This implementation exposes the properties dictionary so the dictionary keys can be referenced like properties (foo.NewProperty = "Cool!"). I override TryGetMember() and TrySetMember() which are fired at runtime every time you access a 'property' on a dynamic instance of this DynamicFoo type. Strong Typing and Dynamic Casting I now can instantiate and use DynamicFoo in a couple of different ways: Strong TypingDynamicFoo fooExplicit = new DynamicFoo(); var fooVar = new DynamicFoo(); These two commands are essentially identical and use strong typing. The compiler generates identical code for both of them. The var statement is merely a compiler directive to infer the type of fooVar at compile time and so the type of fooExplicit is DynamicFoo, just like fooExplicit. This is very static - nothing dynamic about it - and it completely ignores the IDynamicMetaObjectProvider implementation of my class above as it's never used. Using either of these I can access the native properties:DynamicFoo fooExplicit = new DynamicFoo();// static typing assignmentsfooVar.Bar = "Barred!"; fooExplicit.Entered = DateTime.Now; // echo back static values Console.WriteLine(fooVar.Bar); Console.WriteLine(fooExplicit.Entered); but I have no access whatsoever to the properties dictionary. Basically this creates a strongly typed instance of the type with access only to the strongly typed interface. You get no dynamic behavior at all. The IDynamicMetaObjectProvider features don't kick in until you cast the type to dynamic. If I try to access a non-existing property on fooExplicit I get a compilation error that tells me that the property doesn't exist. Again, it's clearly and utterly non-dynamic. Dynamicdynamic fooDynamic = new DynamicFoo(); fooDynamic on the other hand is created as a dynamic type and it's a completely different beast. I can also create a dynamic by simply casting any type to dynamic like this:DynamicFoo fooExplicit = new DynamicFoo(); dynamic fooDynamic = fooExplicit; Note that dynamic typically doesn't require an explicit cast as the compiler automatically performs the cast so there's no need to use as dynamic. Dynamic functionality works at runtime and allows for the dynamic wrapper to look up and call members dynamically. A dynamic type will look for members to access or call in two places: Using the strongly typed members of the object Using theIDynamicMetaObjectProvider Interface methods to access members So rather than statically linking and calling a method or retrieving a property, the dynamic type looks up - at runtime  - where the value actually comes from. It's essentially late-binding which allows runtime determination what action to take when a member is accessed at runtime *if* the member you are accessing does not exist on the object. Class members are checked first before IDynamicMetaObjectProvider interface methods are kick in. All of the following works with the dynamic type:dynamic fooDynamic = new DynamicFoo(); // dynamic typing assignments fooDynamic.NewProperty = "Something new!"; fooDynamic.LastAccess = DateTime.Now; // dynamic assigning static properties fooDynamic.Bar = "dynamic barred"; fooDynamic.Entered = DateTime.Now; // echo back dynamic values Console.WriteLine(fooDynamic.NewProperty); Console.WriteLine(fooDynamic.LastAccess); Console.WriteLine(fooDynamic.Bar); Console.WriteLine(fooDynamic.Entered); The dynamic type can access the native class properties (Bar and Entered) and create and read new ones (NewProperty,LastAccess) all using a single type instance which is pretty cool. As you can see it's pretty easy to create an extensible type this way that can dynamically add members at runtime dynamically. The Alter Ego of IDynamicObject The key point here is that all three statements - explicit, var and dynamic - declare a new DynamicFoo(), but the dynamic declaration results in completely different behavior than the first two simply because the type has been cast to dynamic. Dynamic binding means that the type loses its typical strong typing, compile time features. You can see this easily in the Visual Studio code editor. As soon as you assign a value to a dynamic you lose Intellisense and you see which means there's no Intellisense and no compiler type checking on any members you apply to this instance. If you're new to the dynamic type it might seem really confusing that a single type can behave differently depending on how it is cast, but that's exactly what happens when you use a type that implements IDynamicMetaObjectProvider. Declare the type as its strong type name and you only get to access the native instance members of the type. Declare or cast it to dynamic and you get dynamic behavior which accesses native members plus it uses IDynamicMetaObjectProvider implementation to handle any missing member definitions by running custom code. You can easily cast objects back and forth between dynamic and the original type:dynamic fooDynamic = new DynamicFoo(); fooDynamic.NewProperty = "New Property Value"; DynamicFoo foo = fooDynamic; foo.Bar = "Barred"; Here the code starts out with a dynamic cast and a dynamic assignment. The code then casts back the value to the DynamicFoo. Notice that when casting from dynamic to DynamicFoo and back we typically do not have to specify the cast explicitly - the compiler can induce the type so I don't need to specify as dynamic or as DynamicFoo. Moral of the Story This easy interchange between dynamic and the underlying type is actually super useful, because it allows you to create extensible objects that can expose non-member data stores and expose them as an object interface. You can create an object that hosts a number of strongly typed properties and then cast the object to dynamic and add additional dynamic properties to the same type at runtime. You can easily switch back and forth between the strongly typed instance to access the well-known strongly typed properties and to dynamic for the dynamic properties added at runtime. Keep in mind that dynamic object access has quite a bit of overhead and is definitely slower than strongly typed binding, so if you're accessing the strongly typed parts of your objects you definitely want to use a strongly typed reference. Reserve dynamic for the dynamic members to optimize your code. The real beauty of dynamic is that with very little effort you can build expandable objects or objects that expose different data stores to an object interface. I'll have more on this in my next post when I create a customized and extensible Expando object based on DynamicObject.© Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp  .NET   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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  • Unable to cast transparent proxy to type &lt;type&gt;

    - by Rick Strahl
    This is not the first time I've run into this wonderful error while creating new AppDomains in .NET and then trying to load types and access them across App Domains. In almost all cases the problem I've run into with this error the problem comes from the two AppDomains involved loading different copies of the same type. Unless the types match exactly and come exactly from the same assembly the typecast will fail. The most common scenario is that the types are loaded from different assemblies - as unlikely as that sounds. An Example of Failure To give some context, I'm working on some old code in Html Help Builder that creates a new AppDomain in order to parse assembly information for documentation purposes. I create a new AppDomain in order to load up an assembly process it and then immediately unload it along with the AppDomain. The AppDomain allows for unloading that otherwise wouldn't be possible as well as isolating my code from the assembly that's being loaded. The process to accomplish this is fairly established and I use it for lots of applications that use add-in like functionality - basically anywhere where code needs to be isolated and have the ability to be unloaded. My pattern for this is: Create a new AppDomain Load a Factory Class into the AppDomain Use the Factory Class to load additional types from the remote domain Here's the relevant code from my TypeParserFactory that creates a domain and then loads a specific type - TypeParser - that is accessed cross-AppDomain in the parent domain:public class TypeParserFactory : System.MarshalByRefObject,IDisposable { …/// <summary> /// TypeParser Factory method that loads the TypeParser /// object into a new AppDomain so it can be unloaded. /// Creates AppDomain and creates type. /// </summary> /// <returns></returns> public TypeParser CreateTypeParser() { if (!CreateAppDomain(null)) return null; /// Create the instance inside of the new AppDomain /// Note: remote domain uses local EXE's AppBasePath!!! TypeParser parser = null; try { Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; parser = (TypeParser) this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); } catch (Exception ex) { this.ErrorMessage = ex.GetBaseException().Message; return null; } return parser; } private bool CreateAppDomain(string lcAppDomain) { if (lcAppDomain == null) lcAppDomain = "wwReflection" + Guid.NewGuid().ToString().GetHashCode().ToString("x"); AppDomainSetup setup = new AppDomainSetup(); // *** Point at current directory setup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory; //setup.PrivateBinPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "bin"); this.LocalAppDomain = AppDomain.CreateDomain(lcAppDomain,null,setup); // Need a custom resolver so we can load assembly from non current path AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve); return true; } …} Note that the classes must be either [Serializable] (by value) or inherit from MarshalByRefObject in order to be accessible remotely. Here I need to call methods on the remote object so all classes are MarshalByRefObject. The specific problem code is the loading up a new type which points at an assembly that visible both in the current domain and the remote domain and then instantiates a type from it. This is the code in question:Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; parser = (TypeParser) this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); The last line of code is what blows up with the Unable to cast transparent proxy to type <type> error. Without the cast the code actually returns a TransparentProxy instance, but the cast is what blows up. In other words I AM in fact getting a TypeParser instance back but it can't be cast to the TypeParser type that is loaded in the current AppDomain. Finding the Problem To see what's going on I tried using the .NET 4.0 dynamic type on the result and lo and behold it worked with dynamic - the value returned is actually a TypeParser instance: Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; object objparser = this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); // dynamic works dynamic dynParser = objparser; string info = dynParser.GetVersionInfo(); // method call works // casting fails parser = (TypeParser)objparser; So clearly a TypeParser type is coming back, but nevertheless it's not the right one. Hmmm… mysterious.Another couple of tries reveal the problem however:// works dynamic dynParser = objparser; string info = dynParser.GetVersionInfo(); // method call works // c:\wwapps\wwhelp\wwReflection20.dll (Current Execution Folder) string info3 = typeof(TypeParser).Assembly.CodeBase; // c:\program files\vfp9\wwReflection20.dll (my COM client EXE's folder) string info4 = dynParser.GetType().Assembly.CodeBase; // fails parser = (TypeParser)objparser; As you can see the second value is coming from a totally different assembly. Note that this is even though I EXPLICITLY SPECIFIED an assembly path to load the assembly from! Instead .NET decided to load the assembly from the original ApplicationBase folder. Ouch! How I actually tracked this down was a little more tedious: I added a method like this to both the factory and the instance types and then compared notes:public string GetVersionInfo() { return ".NET Version: " + Environment.Version.ToString() + "\r\n" + "wwReflection Assembly: " + typeof(TypeParserFactory).Assembly.CodeBase.Replace("file:///", "").Replace("/", "\\") + "\r\n" + "Assembly Cur Dir: " + Directory.GetCurrentDirectory() + "\r\n" + "ApplicationBase: " + AppDomain.CurrentDomain.SetupInformation.ApplicationBase + "\r\n" + "App Domain: " + AppDomain.CurrentDomain.FriendlyName + "\r\n"; } For the factory I got: .NET Version: 4.0.30319.239wwReflection Assembly: c:\wwapps\wwhelp\bin\wwreflection20.dllAssembly Cur Dir: c:\wwapps\wwhelpApplicationBase: C:\Programs\vfp9\App Domain: wwReflection534cfa1f For the instance type I got: .NET Version: 4.0.30319.239wwReflection Assembly: C:\\Programs\\vfp9\wwreflection20.dllAssembly Cur Dir: c:\\wwapps\\wwhelpApplicationBase: C:\\Programs\\vfp9\App Domain: wwDotNetBridge_56006605 which clearly shows the problem. You can see that both are loading from different appDomains but the each is loading the assembly from a different location. Probably a better solution yet (for ANY kind of assembly loading problem) is to use the .NET Fusion Log Viewer to trace assembly loads.The Fusion viewer will show a load trace for each assembly loaded and where it's looking to find it. Here's what the viewer looks like: The last trace above that I found for the second wwReflection20 load (the one that is wonky) looks like this:*** Assembly Binder Log Entry (1/13/2012 @ 3:06:49 AM) *** The operation was successful. Bind result: hr = 0x0. The operation completed successfully. Assembly manager loaded from: C:\Windows\Microsoft.NET\Framework\V4.0.30319\clr.dll Running under executable c:\programs\vfp9\vfp9.exe --- A detailed error log follows. === Pre-bind state information === LOG: User = Ras\ricks LOG: DisplayName = wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null (Fully-specified) LOG: Appbase = file:///C:/Programs/vfp9/ LOG: Initial PrivatePath = NULL LOG: Dynamic Base = NULL LOG: Cache Base = NULL LOG: AppName = vfp9.exe Calling assembly : (Unknown). === LOG: This bind starts in default load context. LOG: Using application configuration file: C:\Programs\vfp9\vfp9.exe.Config LOG: Using host configuration file: LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\V4.0.30319\config\machine.config. LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind). LOG: Attempting download of new URL file:///C:/Programs/vfp9/wwReflection20.DLL. LOG: Assembly download was successful. Attempting setup of file: C:\Programs\vfp9\wwReflection20.dll LOG: Entering run-from-source setup phase. LOG: Assembly Name is: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null LOG: Binding succeeds. Returns assembly from C:\Programs\vfp9\wwReflection20.dll. LOG: Assembly is loaded in default load context. WRN: The same assembly was loaded into multiple contexts of an application domain: WRN: Context: Default | Domain ID: 2 | Assembly Name: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null WRN: Context: LoadFrom | Domain ID: 2 | Assembly Name: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null WRN: This might lead to runtime failures. WRN: It is recommended to inspect your application on whether this is intentional or not. WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue. Notice that the fusion log clearly shows that the .NET loader makes no attempt to even load the assembly from the path I explicitly specified. Remember your Assembly Locations As mentioned earlier all failures I've seen like this ultimately resulted from different versions of the same type being available in the two AppDomains. At first sight that seems ridiculous - how could the types be different and why would you have multiple assemblies - but there are actually a number of scenarios where it's quite possible to have multiple copies of the same assembly floating around in multiple places. If you're hosting different environments (like hosting the Razor Engine, or ASP.NET Runtime for example) it's common to create a private BIN folder and it's important to make sure that there's no overlap of assemblies. In my case of Html Help Builder the problem started because I'm using COM interop to access the .NET assembly and the above code. COM Interop has very specific requirements on where assemblies can be found and because I was mucking around with the loader code today, I ended up moving assemblies around to a new location for explicit loading. The explicit load works in the main AppDomain, but failed in the remote domain as I showed. The solution here was simple enough: Delete the extraneous assembly which was left around by accident. Not a common problem, but one that when it bites is pretty nasty to figure out because it seems so unlikely that types wouldn't match. I know I've run into this a few times and writing this down hopefully will make me remember in the future rather than poking around again for an hour trying to debug the issue as I did today. Hopefully it'll save some of you some time as well in the future.© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  COM   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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  • Problems with opening CHM Help files from Network or Internet

    - by Rick Strahl
    As a publisher of a Help Creation tool called Html Help Help Builder, I’ve seen a lot of problems with help files that won't properly display actual topic content and displays an error message for topics instead. Here’s the scenario: You go ahead and happily build your fancy, schmanzy Help File for your application and deploy it to your customer. Or alternately you've created a help file and you let your customers download them off the Internet directly or in a zip file. The customer downloads the file, opens the zip file and copies the help file contained in the zip file to disk. She then opens the help file and finds the following unfortunate result:     The help file  comes up with all topics in the tree on the left, but a Navigation to the WebPage was cancelled or Operation Aborted error in the Help Viewer's content window whenever you try to open a topic. The CHM file obviously opened since the topic list is there, but the Help Viewer refuses to display the content. Looks like a broken help file, right? But it's not - it's merely a Windows security 'feature' that tries to be overly helpful in protecting you. The reason this happens is because files downloaded off the Internet - including ZIP files and CHM files contained in those zip files - are marked as as coming from the Internet and so can potentially be malicious, so do not get browsing rights on the local machine – they can’t access local Web content, which is exactly what help topics are. If you look at the URL of a help topic you see something like this:   mk:@MSITStore:C:\wwapps\wwIPStuff\wwipstuff.chm::/indexpage.htm which points at a special Microsoft Url Moniker that in turn points the CHM file and a relative path within that HTML help file. Try pasting a URL like this into Internet Explorer and you'll see the help topic pop up in your browser (along with a warning most likely). Although the URL looks weird this still equates to a call to the local computer zone, the same as if you had navigated to a local file in IE which by default is not allowed.  Unfortunately, unlike Internet Explorer where you have the option of clicking a security toolbar, the CHM viewer simply refuses to load the page and you get an error page as shown above. How to Fix This - Unblock the Help File There's a workaround that lets you explicitly 'unblock' a CHM help file. To do this: Open Windows Explorer Find your CHM file Right click and select Properties Click the Unblock button on the General tab Here's what the dialog looks like:   Clicking the Unblock button basically, tells Windows that you approve this Help File and allows topics to be viewed.   Is this insecure? Not unless you're running a really old Version of Windows (XP pre-SP1). In recent versions of Windows Internet Explorer pops up various security dialogs or fires script errors when potentially malicious operations are accessed (like loading Active Controls), so it's relatively safe to run local content in the CHM viewer. Since most help files don't contain script or only load script that runs pure JavaScript access web resources this works fine without issues. How to avoid this Problem As an application developer there's a simple solution around this problem: Always install your Help Files with an Installer. The above security warning pop up because Windows can't validate the source of the CHM file. However, if the help file is installed as part of an installation the installation and all files associated with that installation including the help file are trusted. A fully installed Help File of an application works just fine because it is trusted by Windows. Summary It's annoying as all hell that this sort of obtrusive marking is necessary, but it's admittedly a necessary evil because of Microsoft's use of the insecure Internet Explorer engine that drives the CHM Html Engine's topic viewer. Because help files are viewing local content and script is allowed to execute in CHM files there's potential for malicious code hiding in CHM files and the above precautions are supposed to avoid any issues. © Rick Strahl, West Wind Technologies, 2005-2012 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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  • IE9 not rendering box-shadow Elements inside of Table Cells

    - by Rick Strahl
    Ran into an annoying problem today with IE 9. Slowly updating some older sites with CSS 3 tags and for the most part IE9 does a reasonably decent job of working with the new CSS 3 features. Not all by a long shot but at least some of the more useful ones like border-radius and box-shadow are supported. Until today I was happy to see that IE supported box-shadow just fine, but I ran into a problem with some old markup that uses tables for its main layout sections. I found that inside of a table cell IE fails to render a box-shadow. Below are images from Chrome (left) and IE 9 (right) of the same content: The download and purchase images are rendered with: <a href="download.asp" style="display:block;margin: 10px;"><img src="../images/download.gif" class="boxshadow roundbox" /></a> where the .boxshadow and .roundbox styles look like this:.boxshadow { -moz-box-shadow: 3px 3px 5px #535353; -webkit-box-shadow: 3px 3px 5px #535353; box-shadow: 3px 3px 5px #535353; } .roundbox { -moz-border-radius: 6px 6px 6px 6px; -webkit-border-radius: 6px; border-radius: 6px 6px 6px 6px; } And the Problem is… collapsed Table Borders Now normally these two styles work just fine in IE 9 when applied to elements. But the box-shadow doesn't work inside of this markup - because the parent container is a table cell.<td class="sidebar" style="border-collapse: collapse"> … <a href="download.asp" style="display:block;margin: 10px;"><img src="../images/download.gif" class="boxshadow roundbox" /></a> …</td> This HTML causes the image to not show a shadow. In actuality I'm not styling inline, but as part of my browser Reset I have the following in my master .css file:table { border-collapse: collapse; border-spacing: 0; } which has the same effect as the inline style. border-collapse by default inherits from the parent and so the TD inherits from table and tr - so TD tags are effectively collapsed. You can check out a test document that demonstrates this behavior here in this CodePaste.net snippet or run it here. How to work around this Issue To get IE9 to render the shadows inside of the TD tag correctly, I can just change the style explicitly NOT to use border-collapse:<td class="sidebar" style="border-collapse: separate; border-width: 0;"> Or better yet (thanks to David's comment below), you can add the border-collapse: separate to the .boxshadow style like this:.boxshadow { -moz-box-shadow: 3px 3px 5px #535353; -webkit-box-shadow: 3px 3px 5px #535353; box-shadow: 3px 3px 5px #535353; border-collapse: separate; } With either of these approaches IE renders the shadows correctly. Do you really need border-collapse? Should you bother with border-collapse? I think so! Collapsed borders render flat as a single fat line if a border-width and border-color are assigned, while separated borders render a thin line with a bunch of weird white space around it or worse render a old skool 3D raised border which is terribly ugly as well. So as a matter of course in any app my browser Reset includes the above code to make sure all tables with borders render the same flat borders. As you probably know, IE has all sorts of rendering issues in tables and on backgrounds (opacity backgrounds or image backgrounds) most of which is caused by the way that IE internally uses ActiveX filters to apply these effects. Apparently collapsed borders are yet one more item that causes problems with rendering. There you have it. Another crappy failure in IE we have to check for now, just one more reason to hate Internet Explorer. Luckily this one has a reasonably easy workaround. I hope this helps out somebody and saves them the hour I spent trying to figure out what caused this problem in the first place. Resources Sample HTML document that demonstrates the behavior Run the Sample© Rick Strahl, West Wind Technologies, 2005-2012Posted in HTML  Internet Explorer   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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  • XmlWriter and lower ASCII characters

    - by Rick Strahl
    Ran into an interesting problem today on my CodePaste.net site: The main RSS and ATOM feeds on the site were broken because one code snippet on the site contained a lower ASCII character (CHR(3)). I don't think this was done on purpose but it was enough to make the feeds fail. After quite a bit of debugging and throwing in a custom error handler into my actual feed generation code that just spit out the raw error instead of running it through the ASP.NET MVC and my own error pipeline I found the actual error. The lovely base exception and error trace I got looked like this: Error: '', hexadecimal value 0x03, is an invalid character. at System.Xml.XmlUtf8RawTextWriter.InvalidXmlChar(Int32 ch, Byte* pDst, Boolean entitize)at System.Xml.XmlUtf8RawTextWriter.WriteElementTextBlock(Char* pSrc, Char* pSrcEnd)at System.Xml.XmlUtf8RawTextWriter.WriteString(String text)at System.Xml.XmlWellFormedWriter.WriteString(String text)at System.Xml.XmlWriter.WriteElementString(String localName, String ns, String value)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteItemContents(XmlWriter writer, SyndicationItem item, Uri feedBaseUri)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteItem(XmlWriter writer, SyndicationItem item, Uri feedBaseUri)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteItems(XmlWriter writer, IEnumerable`1 items, Uri feedBaseUri)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteFeed(XmlWriter writer)at System.ServiceModel.Syndication.Rss20FeedFormatter.WriteTo(XmlWriter writer)at CodePasteMvc.Controllers.ApiControllerBase.GetFeed(Object instance) in C:\Projects2010\CodePaste\CodePasteMvc\Controllers\ApiControllerBase.cs:line 131 XML doesn't like extended ASCII Characters It turns out the issue is that XML in general does not deal well with lower ASCII characters. According to the XML spec it looks like any characters below 0x09 are invalid. If you generate an XML document in .NET with an embedded &#x3; entity (as mine did to create the error above), you tend to get an XML document error when displaying it in a viewer. For example, here's what the result of my  feed output looks like with the invalid character embedded inside of Chrome which displays RSS feeds as raw XML by default: Other browsers show similar error messages. The nice thing about Chrome is that you can actually view source and jump down to see the line that causes the error which allowed me to track down the actual message that failed. If you create an XML document that contains a 0x03 character the XML writer fails outright with the error: '', hexadecimal value 0x03, is an invalid character. The good news is that this behavior is overridable so XML output can at least be created by using the XmlSettings object when configuring the XmlWriter instance. In my RSS configuration code this looks something like this:MemoryStream ms = new MemoryStream(); var settings = new XmlWriterSettings() { CheckCharacters = false }; XmlWriter writer = XmlWriter.Create(ms,settings); and voila the feed now generates. Now generally this is probably NOT a good idea, because as mentioned above these characters are illegal and if you view a raw XML document you'll get validation errors. Luckily though most RSS feed readers however don't care and happily accept and display the feed correctly, which is good because it got me over an embarrassing hump until I figured out a better solution. How to handle extended Characters? I was glad to get the feed fixed for the time being, but now I was still stuck with an interesting dilemma. CodePaste.net accepts user input for code snippets and those code snippets can contain just about anything. This means that ASP.NET's standard request filtering cannot be applied to this content. The code content displayed is encoded before display so for the HTML end the CHR(3) input is not really an issue. While invisible characters are hardly useful in user input it's not uncommon that odd characters show up in code snippets. You know the old fat fingering that happens when you're in the middle of a coding session and those invisible characters do end up sometimes in code editors and then end up pasted into the HTML textbox for pasting as a Codepaste.net snippet. The question is how to filter this text? Looking back at the XML Charset Spec it looks like all characters below 0x20 (space) except for 0x09 (tab), 0x0A (LF), 0x0D (CR) are illegal. So applying the following filter with a RegEx should work to remove invalid characters:string code = Regex.Replace(item.Code, @"[\u0000-\u0008,\u000B,\u000C,\u000E-\u001F]", ""); Applying this RegEx to the code snippet (and title) eliminates the problems and the feed renders cleanly.© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  XML   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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  • ASP.NET MVC 4: Short syntax for script and style bundling

    - by DigiMortal
    ASP.NET MVC 4 introduces new methods for style and scripts bundling. I found something brilliant there I want to introduce you. In this posting I will show you how easy it is to include whole folder with stylesheets or JavaScripts to your page. I’m using ASP.NET MVC 4 Internet Site template for this example. When we open layout pages located in shared views folder we can see something like this in layout file header: <link href="@System.Web.Optimization.BundleTable.Bundles.ResolveBundleUrl("~/Content/css")" rel="stylesheet" type="text/css" />    <link href="@System.Web.Optimization.BundleTable.Bundles.ResolveBundleUrl("~/Content/themes/base/css")" rel="stylesheet" type="text/css" />    <script src="@System.Web.Optimization.BundleTable.Bundles.ResolveBundleUrl("~/Scripts/js")"></script> Let’s take the last line and modify it so it looks like this: <script src="/Scripts/js"></script> After saving the layout page let’s run browser and see what is coming in over network. As you can see the request to folder ended up with result code 200 which means that request was successful. 327.2KB was received and it is not mark-up size for error page or directory index. Here is the body of response: I scrolled down to point where one script ends and another one starts when I made the screenshot above. All scripts delivered with ASP.NET MVC project templates start with this green note. So now we can be sure that the request to scripts folder ended up with bundled script and not with something else. Conclusion Script and styles bundling uses currently by default long syntax where bundling is done through Bundling class. We can still avoid those long lines and use extremely short syntax for script and styles bundling – we just write usual script or link tag and give folder URL as source. ASP.NET MVC 4 is smart enough to combine styles or scripts when request like this comes in.

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  • Drawing transparent glyphs on the HTML canvas

    - by Bertrand Le Roy
    The HTML canvas has a set of methods, createImageData and putImageData, that look like they will enable you to draw transparent shapes pixel by pixel. The data structures that you manipulate with these methods are pseudo-arrays of pixels, with four bytes per pixel. One byte for red, one for green, one for blue and one for alpha. This alpha byte makes one believe that you are going to be able to manage transparency, but that’s a lie. Here is a little script that attempts to overlay a simple generated pattern on top of a uniform background: var wrong = document.getElementById("wrong").getContext("2d"); wrong.fillStyle = "#ffd42a"; wrong.fillRect(0, 0, 64, 64); var overlay = wrong.createImageData(32, 32), data = overlay.data; fill(data); wrong.putImageData(overlay, 16, 16); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } where the fill method is setting the pixels in the lower-left half of the overlay to opaque red, and the rest to transparent black. And here’s how it renders: As you can see, the transparency byte was completely ignored. Or was it? in fact, what happens is more subtle. What happens is that the pixels from the image data, including their alpha byte, replaced the existing pixels of the canvas. So the alpha byte is not lost, it’s just that it wasn’t used by putImageData to combine the new pixels with the existing ones. This is in fact a clue to how to write a putImageData that works: we can first dump that image data into an intermediary canvas, and then compose that temporary canvas onto our main canvas. The method that we can use for this composition is drawImage, which works not only with image objects, but also with canvas objects. var right = document.getElementById("right").getContext("2d"); right.fillStyle = "#ffd42a"; right.fillRect(0, 0, 64, 64); var overlay = wrong.createImageData(32, 32), data = overlay.data; fill(data); var overlayCanvas = document.createElement("canvas"); overlayCanvas.width = overlayCanvas.height = 32; overlayCanvas.getContext("2d").putImageData(overlay, 0, 0); right.drawImage(overlayCanvas, 16, 16); And there is is, a version of putImageData that works like it should always have:

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  • ASP.NET Web API - Screencast series Part 4: Paging and Querying

    - by Jon Galloway
    We're continuing a six part series on ASP.NET Web API that accompanies the getting started screencast series. This is an introductory screencast series that walks through from File / New Project to some more advanced scenarios like Custom Validation and Authorization. The screencast videos are all short (3-5 minutes) and the sample code for the series is both available for download and browsable online. I did the screencasts, but the samples were written by the ASP.NET Web API team. In Part 1 we looked at what ASP.NET Web API is, why you'd care, did the File / New Project thing, and did some basic HTTP testing using browser F12 developer tools. In Part 2 we started to build up a sample that returns data from a repository in JSON format via GET methods. In Part 3, we modified data on the server using DELETE and POST methods. In Part 4, we'll extend on our simple querying methods form Part 2, adding in support for paging and querying. This part shows two approaches to querying data (paging really just being a specific querying case) - you can do it yourself using parameters passed in via querystring (as well as headers, other route parameters, cookies, etc.). You're welcome to do that if you'd like. What I think is more interesting here is that Web API actions that return IQueryable automatically support OData query syntax, making it really easy to support some common query use cases like paging and filtering. A few important things to note: This is just support for OData query syntax - you're not getting back data in OData format. The screencast demonstrates this by showing the GET methods are continuing to return the same JSON they did previously. So you don't have to "buy in" to the whole OData thing, you're just able to use the query syntax if you'd like. This isn't full OData query support - full OData query syntax includes a lot of operations and features - but it is a pretty good subset: filter, orderby, skip, and top. All you have to do to enable this OData query syntax is return an IQueryable rather than an IEnumerable. Often, that could be as simple as using the AsQueryable() extension method on your IEnumerable. Query composition support lets you layer queries intelligently. If, for instance, you had an action that showed products by category using a query in your repository, you could also support paging on top of that. The result is an expression tree that's evaluated on-demand and includes both the Web API query and the underlying query. So with all those bullet points and big words, you'd think this would be hard to hook up. Nope, all I did was change the return type from IEnumerable<Comment> to IQueryable<Comment> and convert the Get() method's IEnumerable result using the .AsQueryable() extension method. public IQueryable<Comment> GetComments() { return repository.Get().AsQueryable(); } You still need to build up the query to provide the $top and $skip on the client, but you'd need to do that regardless. Here's how that looks: $(function () { //--------------------------------------------------------- // Using Queryable to page //--------------------------------------------------------- $("#getCommentsQueryable").click(function () { viewModel.comments([]); var pageSize = $('#pageSize').val(); var pageIndex = $('#pageIndex').val(); var url = "/api/comments?$top=" + pageSize + '&$skip=' + (pageIndex * pageSize); $.getJSON(url, function (data) { // Update the Knockout model (and thus the UI) with the comments received back // from the Web API call. viewModel.comments(data); }); return false; }); }); And the neat thing is that - without any modification to our server-side code - we can modify the above jQuery call to request the comments be sorted by author: $(function () { //--------------------------------------------------------- // Using Queryable to page //--------------------------------------------------------- $("#getCommentsQueryable").click(function () { viewModel.comments([]); var pageSize = $('#pageSize').val(); var pageIndex = $('#pageIndex').val(); var url = "/api/comments?$top=" + pageSize + '&$skip=' + (pageIndex * pageSize) + '&$orderby=Author'; $.getJSON(url, function (data) { // Update the Knockout model (and thus the UI) with the comments received back // from the Web API call. viewModel.comments(data); }); return false; }); }); So if you want to make use of OData query syntax, you can. If you don't like it, you're free to hook up your filtering and paging however you think is best. Neat. In Part 5, we'll add on support for Data Annotation based validation using an Action Filter.

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  • ASP.NET Web API - Screencast series Part 3: Delete and Update

    - by Jon Galloway
    We're continuing a six part series on ASP.NET Web API that accompanies the getting started screencast series. This is an introductory screencast series that walks through from File / New Project to some more advanced scenarios like Custom Validation and Authorization. The screencast videos are all short (3-5 minutes) and the sample code for the series is both available for download and browsable online. I did the screencasts, but the samples were written by the ASP.NET Web API team. In Part 1 we looked at what ASP.NET Web API is, why you'd care, did the File / New Project thing, and did some basic HTTP testing using browser F12 developer tools. In Part 2 we started to build up a sample that returns data from a repository in JSON format via GET methods. In Part 3, we'll start to modify data on the server using DELETE and POST methods. So far we've been looking at GET requests, and the difference between standard browsing in a web browser and navigating an HTTP API isn't quite as clear. Delete is where the difference becomes more obvious. With a "traditional" web page, to delete something'd probably have a form that POSTs a request back to a controller that needs to know that it's really supposed to be deleting something even though POST was really designed to create things, so it does the work and then returns some HTML back to the client that says whether or not the delete succeeded. There's a good amount of plumbing involved in communicating between client and server. That gets a lot easier when we just work with the standard HTTP DELETE verb. Here's how the server side code works: public Comment DeleteComment(int id) { Comment comment; if (!repository.TryGet(id, out comment)) throw new HttpResponseException(HttpStatusCode.NotFound); repository.Delete(id); return comment; } If you look back at the GET /api/comments code in Part 2, you'll see that they start the exact same because the use cases are kind of similar - we're looking up an item by id and either displaying it or deleting it. So the only difference is that this method deletes the comment once it finds it. We don't need to do anything special to handle cases where the id isn't found, as the same HTTP 404 handling works fine here, too. Pretty much all "traditional" browsing uses just two HTTP verbs: GET and POST, so you might not be all that used to DELETE requests and think they're hard. Not so! Here's the jQuery method that calls the /api/comments with the DELETE verb: $(function() { $("a.delete").live('click', function () { var id = $(this).data('comment-id'); $.ajax({ url: "/api/comments/" + id, type: 'DELETE', cache: false, statusCode: { 200: function(data) { viewModel.comments.remove( function(comment) { return comment.ID == data.ID; } ); } } }); return false; }); }); So in order to use the DELETE verb instead of GET, we're just using $.ajax() and setting the type to DELETE. Not hard. But what's that statusCode business? Well, an HTTP status code of 200 is an OK response. Unless our Web API method sets another status (such as by throwing the Not Found exception we saw earlier), the default response status code is HTTP 200 - OK. That makes the jQuery code pretty simple - it calls the Delete action, and if it gets back an HTTP 200, the server-side delete was successful so the comment can be deleted. Adding a new comment uses the POST verb. It starts out looking like an MVC controller action, using model binding to get the new comment from JSON data into a c# model object to add to repository, but there are some interesting differences. public HttpResponseMessage<Comment> PostComment(Comment comment) { comment = repository.Add(comment); var response = new HttpResponseMessage<Comment>(comment, HttpStatusCode.Created); response.Headers.Location = new Uri(Request.RequestUri, "/api/comments/" + comment.ID.ToString()); return response; } First off, the POST method is returning an HttpResponseMessage<Comment>. In the GET methods earlier, we were just returning a JSON payload with an HTTP 200 OK, so we could just return the  model object and Web API would wrap it up in an HttpResponseMessage with that HTTP 200 for us (much as ASP.NET MVC controller actions can return strings, and they'll be automatically wrapped in a ContentResult). When we're creating a new comment, though, we want to follow standard REST practices and return the URL that points to the newly created comment in the Location header, and we can do that by explicitly creating that HttpResposeMessage and then setting the header information. And here's a key point - by using HTTP standard status codes and headers, our response payload doesn't need to explain any context - the client can see from the status code that the POST succeeded, the location header tells it where to get it, and all it needs in the JSON payload is the actual content. Note: This is a simplified sample. Among other things, you'll need to consider security and authorization in your Web API's, and especially in methods that allow creating or deleting data. We'll look at authorization in Part 6. As for security, you'll want to consider things like mass assignment if binding directly to model objects, etc. In Part 4, we'll extend on our simple querying methods form Part 2, adding in support for paging and querying.

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  • ASP.NET Web API - Screencast series Part 2: Getting Data

    - by Jon Galloway
    We're continuing a six part series on ASP.NET Web API that accompanies the getting started screencast series. This is an introductory screencast series that walks through from File / New Project to some more advanced scenarios like Custom Validation and Authorization. The screencast videos are all short (3-5 minutes) and the sample code for the series is both available for download and browsable online. I did the screencasts, but the samples were written by the ASP.NET Web API team. In Part 1 we looked at what ASP.NET Web API is, why you'd care, did the File / New Project thing, and did some basic HTTP testing using browser F12 developer tools. This second screencast starts to build out the Comments example - a JSON API that's accessed via jQuery. This sample uses a simple in-memory repository. At this early stage, the GET /api/values/ just returns an IEnumerable<Comment>. In part 4 we'll add on paging and filtering, and it gets more interesting.   The get by id (e.g. GET /api/values/5) case is a little more interesting. The method just returns a Comment if the Comment ID is valid, but if it's not found we throw an HttpResponseException with the correct HTTP status code (HTTP 404 Not Found). This is an important thing to get - HTTP defines common response status codes, so there's no need to implement any custom messaging here - we tell the requestor that the resource the requested wasn't there.  public Comment GetComment(int id) { Comment comment; if (!repository.TryGet(id, out comment)) throw new HttpResponseException(HttpStatusCode.NotFound); return comment; } This is great because it's standard, and any client should know how to handle it. There's no need to invent custom messaging here, and we can talk to any client that understands HTTP - not just jQuery, and not just browsers. But it's crazy easy to consume an HTTP API that returns JSON via jQuery. The example uses Knockout to bind the JSON values to HTML elements, but the thing to notice is that calling into this /api/coments is really simple, and the return from the $.get() method is just JSON data, which is really easy to work with in JavaScript (since JSON stands for JavaScript Object Notation and is the native serialization format in Javascript). $(function() { $("#getComments").click(function () { // We're using a Knockout model. This clears out the existing comments. viewModel.comments([]); $.get('/api/comments', function (data) { // Update the Knockout model (and thus the UI) with the comments received back // from the Web API call. viewModel.comments(data); }); }); }); That's it! Easy, huh? In Part 3, we'll start modifying data on the server using POST and DELETE.

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  • ASP.NET Web API - Screencast series with downloadable sample code - Part 1

    - by Jon Galloway
    There's a lot of great ASP.NET Web API content on the ASP.NET website at http://asp.net/web-api. I mentioned my screencast series in original announcement post, but we've since added the sample code so I thought it was worth pointing the series out specifically. This is an introductory screencast series that walks through from File / New Project to some more advanced scenarios like Custom Validation and Authorization. The screencast videos are all short (3-5 minutes) and the sample code for the series is both available for download and browsable online. I did the screencasts, but the samples were written by the ASP.NET Web API team. So - let's watch them together! Grab some popcorn and pay attention, because these are short. After each video, I'll talk about what I thought was important. I'm embedding the videos using HTML5 (MP4) with Silverlight fallback, but if something goes wrong or your browser / device / whatever doesn't support them, I'll include the link to where the videos are more professionally hosted on the ASP.NET site. Note also if you're following along with the samples that, since Part 1 just looks at the File / New Project step, the screencast part numbers are one ahead of the sample part numbers - so screencast 4 matches with sample code demo 3. Note: I started this as one long post for all 6 parts, but as it grew over 2000 words I figured it'd be better to break it up. Part 1: Your First Web API [Video and code on the ASP.NET site] This screencast starts with an overview of why you'd want to use ASP.NET Web API: Reach more clients (thinking beyond the browser to mobile clients, other applications, etc.) Scale (who doesn't love the cloud?!) Embrace HTTP (a focus on HTTP both on client and server really simplifies and focuses service interactions) Next, I start a new ASP.NET Web API application and show some of the basics of the ApiController. We don't write any new code in this first step, just look at the example controller that's created by File / New Project. using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace NewProject_Mvc4BetaWebApi.Controllers { public class ValuesController : ApiController { // GET /api/values public IEnumerable<string> Get() { return new string[] { "value1", "value2" }; } // GET /api/values/5 public string Get(int id) { return "value"; } // POST /api/values public void Post(string value) { } // PUT /api/values/5 public void Put(int id, string value) { } // DELETE /api/values/5 public void Delete(int id) { } } } Finally, we walk through testing the output of this API controller using browser tools. There are several ways you can test API output, including Fiddler (as described by Scott Hanselman in this post) and built-in developer tools available in all modern browsers. For simplicity I used Internet Explorer 9 F12 developer tools, but you're of course welcome to use whatever you'd like. A few important things to note: This class derives from an ApiController base class, not the standard ASP.NET MVC Controller base class. They're similar in places where API's and HTML returning controller uses are similar, and different where API and HTML use differ. A good example of where those things are different is in the routing conventions. In an HTTP controller, there's no need for an "action" to be specified, since the HTTP verbs are the actions. We don't need to do anything to map verbs to actions; when a request comes in to /api/values/5 with the DELETE HTTP verb, it'll automatically be handled by the Delete method in an ApiController. The comments above the API methods show sample URL's and HTTP verbs, so we can test out the first two GET methods by browsing to the site in IE9, hitting F12 to bring up the tools, and entering /api/values in the URL: That sample action returns a list of values. To get just one value back, we'd browse to /values/5: That's it for Part 1. In Part 2 we'll look at getting data (beyond hardcoded strings) and start building out a sample application.

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  • It has been a long time since last post

    - by The Official Microsoft IIS Site
    Wow, just realized that in the last 6 months I’ve only had a chance to post 2 items and I think it is about time to start this going again. So why this much silence? Well, About 8 months ago a couple of big changes happened at my division as described in this link . As part of that transition my responsibilities changed and I transitioned from being the Development Manager for the Web Platform (IIS, WebMatrix, WebDeploy, etc…) to take a new role and start a new team that we called Azure UX team....(read more)

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  • Mobile: Wrox Cross Platform Mobile Development - iPhone, iPad, Android, and everything with .NET & C#

    - by Wallym
    Wrox has produced a bundle of their 3 best selling mobile development books and it is available as of Today (March 16). A bundle of 3 best-selling and respected mobile development e-books from Wrox form a complete library on the key tools and techniques for developing apps across the hottest platforms including Android and iOS. This collection includes the full content of these three books, at a special price: Professional Android Programming with Mono for Android and .NET/C#, ISBN: 9781118026434, by Wallace B. McClure, Nathan Blevins, John J. Croft, IV, Jonathan Dick, and Chris Hardy Professional iPhone Programming with MonoTouch and .NET/C#, ISBN: 9780470637821, by Wallace B. McClure, Rory Blyth, Craig Dunn, Chris Hardy, and Martin Bowling Professional Cross-Platform Mobile Development in C#, ISBN: 9781118157701, by Scott Olson, John Hunter, Ben Horgen, and Kenny Goers Remember, go buy 8-10 copies of the 3 book set for the ones you love. They will make great and romantic gifts!!

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  • A better way to encourage contributions to OSS

    - by Daniel Cazzulino
    Currently in the .NET world, most OSS projects are available via a NuGet package. Users have a very easy path towards *using* the project right away. But let’s say they encounter some isssue (maybe a bug, maybe a potential improvement) with the library. At this point, going from user to contributor (of a fix, or a good bug repro or even a spike for a new feature) is a very steep and non trivial multi-step process of registering with some open source hosting site (codeplex, github, bitbucket, etc.), learning how to grab the latest sources, build the project, formulate a patch (or fork the code), learn the source control software they use (mercurial, git, svn, tfs), install whatever tools are needed for it, read about the contributors workflow for the project (do you fork &amp; send pull requests? do you just send a patch file? do you just send a snippet? a unit test? etc.), and on, and on, and on. Granted, you may be lucky and already know the source control system the project uses, but in really, I’d say the chances are pretty low. I believe most developers *using* OSS are far from familiar with them, much less with contributing back to various projects. We OSS devs like to be on the cutting edge all the time, ya’ know, always jumping on the new SCC system, the new hosting site, the new agile way of managing work items, bug tracking, code reviews, etc. etc. etc.. But most of our OSS users are largely the “... Read full article

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  • Obtaining positional information in the IEnumerable Select extension method

    - by Kyle Burns
    This blog entry is intended to provide a narrow and brief look into a way to use the Select extension method that I had until recently overlooked. Every developer who is using IEnumerable extension methods to work with data has been exposed to the Select extension method, because it is a pretty critical piece of almost every query over a collection of objects.  The method is defined on type IEnumerable and takes as its argument a function that accepts an item from the collection and returns an object which will be an item within the returned collection.  This allows you to perform transformations on the source collection.  A somewhat contrived example would be the following code that transforms a collection of strings into a collection of anonymous objects: 1: var media = new[] {"book", "cd", "tape"}; 2: var transformed = media.Select( item => 3: { 4: Media = item 5: } ); This code transforms the array of strings into a collection of objects which each have a string property called Media. If every developer using the LINQ extension methods already knows this, why am I blogging about it?  I’m blogging about it because the method has another overload that I hadn’t seen before I needed it a few weeks back and I thought I would share a little about it with whoever happens upon my blog.  In the other overload, the function defined in the first overload as: 1: Func<TSource, TResult> is instead defined as: 1: Func<TSource, int, TResult>   The additional parameter is an integer representing the current element’s position in the enumerable sequence.  I used this information in what I thought was a pretty cool way to compare collections and I’ll probably blog about that sometime in the near future, but for now we’ll continue with the contrived example I’ve already started to keep things simple and show how this works.  The following code sample shows how the positional information could be used in an alternating color scenario.  I’m using a foreach loop because IEnumerable doesn’t have a ForEach extension, but many libraries do add the ForEach extension to IEnumerable so you can update the code if you’re using one of these libraries or have created your own. 1: var media = new[] {"book", "cd", "tape"}; 2: foreach (var result in media.Select( 3: (item, index) => 4: new { Item = item, Index = index })) 5: { 6: Console.ForegroundColor = result.Index % 2 == 0 7: ? ConsoleColor.Blue : ConsoleColor.Yellow; 8: Console.WriteLine(result.Item); 9: }

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  • Converting NUnit tests to MSUnit.

    - by TATWORTH
    I created the MSTest project by creating a new class library project and copying the test classes to it. I then followed the instructions in the following posts.http://social.msdn.microsoft.com/Forums/en/vststest/thread/eeb42224-bc1f-476d-98b4-93d0daf44aadhttp://dangerz.blogspot.co.uk/2012/01/converting-nunit-to-mstest.htmlHowever I did not need to add the GUID fix as I used ReSharper to run both sets of tests.

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  • Starting a new Open-source project - 2 - CommonEventLog is available.

    - by TATWORTH
    On this project I needed to provide unit tests both in NUnit and MSTest. I will write about this later.Once done, both projects ran without errors being detected. I loaded up the main project as source to CodePlex. (Resharper was very helpful in that it would run both sets of tests - thank you Jet Brains!) Can't code withoutIn-depth C# code analysis with instant errorand warning highlighting and quick-fixes

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  • Mirroring git and mercurial repos the lazy way

    - by Greg Malcolm
    I maintain Python Koans on mirrored on both Github using git and Bitbucket using mercurial. I get pull requests from both repos but it turns out keeping the two repos in sync is pretty easy. Here is how it's done... Assuming I’m starting again on a clean laptop, first I clone both repos ~/git $ hg clone https://bitbucket.org/gregmalcolm/python_koans ~/git $ git clone [email protected]:gregmalcolm/python_koans.git python_koans2 The only thing that makes a folder a git or mercurial repository is the .hg folder in the root of python_koans and the .git folder in the root of python_koans2. So I just need to move the .git folder over into the python_koans folder I'm using for mercurial: ~/git $ rm -rf python_koans/.git ~/git $ mv python_koans2/.git python_koans ~/git $ ls -la python_koans total 48 drwxr-xr-x 11 greg staff 374 Mar 17 15:10 . drwxr-xr-x 62 greg staff 2108 Mar 17 14:58 .. drwxr-xr-x 12 greg staff 408 Mar 17 14:58 .git -rw-r--r-- 1 greg staff 34 Mar 17 14:54 .gitignore drwxr-xr-x 13 greg staff 442 Mar 17 14:54 .hg -rw-r--r-- 1 greg staff 48 Mar 17 14:54 .hgignore -rw-r--r-- 1 greg staff 365 Mar 17 14:54 Contributor Notes.txt -rw-r--r-- 1 greg staff 1082 Mar 17 14:54 MIT-LICENSE -rw-r--r-- 1 greg staff 5765 Mar 17 14:54 README.txt drwxr-xr-x 10 greg staff 340 Mar 17 14:54 python 2 drwxr-xr-x 10 greg staff 340 Mar 17 14:54 python 3 That’s about it! Now git and mercurial are tracking files in the same folder. Of course you will still need to set up your .gitignore to ignore mercurial’s dotfiles and .hgignore to ignore git’s dotfiles or there will be squabbling in the backseat. ~/git $ cd python_koans/ ~/git/python_koans $ cat .gitignore *.pyc *.swp .DS_Store answers .hg <-- Ignore mercurial ~/git/python_koans $ cat .hgignore syntax: glob *.pyc *.swp .DS_Store answers .git <-- Ignore git Because both my mirrors are both identical as far as tracked files are concerned I won’t yet see anything if I check statuses at this point: ~/git/python_koans $ git status # On branch master nothing to commit (working directory clean) ~/git/python_koans $ hg status ~/git/python_koans But how about if I accept a pull request from the bitbucket (mercuial) site? ~/git/python_koans $ hg status ~/git/python_koans $ git status # On branch master # Your branch is behind 'origin/master' by 1 commit, and can be fast-forwarded. # # Changed but not updated: # (use "git add <file>..." to update what will be committed) # (use "git checkout -- <file>..." to discard changes in working directory) # # modified: python 2/koans/about_decorating_with_classes.py # modified: python 2/koans/about_iteration.py # modified: python 2/koans/about_with_statements.py # modified: python 3/koans/about_decorating_with_classes.py # modified: python 3/koans/about_iteration.py # modified: python 3/koans/about_with_statements.py Mercurial doesn’t have any changes to track right now, but git has changes. Commit and push them up to github and balance is restored to the force: ~/git/python_koans $ git commit -am "Merge from bitbucket mirror: 'gpiancastelli - Fix for issue #21 and some other tweaks'" [master 79ca184] Merge from bitbucket mirror: 'gpiancastelli - Fix for issue #21 and some other tweaks' 6 files changed, 78 insertions(+), 63 deletions(-) ~/git/python_koans $ git push origin master Or just use hg-git? The github developers have actually published a plugin for automatic mirroring: http://hg-git.github.com I haven’t used it because at the time I tried it a couple of years ago I was having problems getting all the parts to play nice with each other. Probably works fine now though..

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  • The World of SQL Database Deployment

    - by GGBlogger
    In my early development days, I used Microsoft Access for building databases. It made things easy since I only needed to package the database with the installation package so my clients would have access to it. When we began the development of a new package in Visual Studio .NET I decided to use SQL Server Express. It was free and provided good tools - also free. I thought it was a tremendous idea until it came time to distribute our new software! What a surprise. The nightmare Ah, the choices! Detach the database and have the client reattach it to a newly installed – oh wait. FIRST my new client needs to download and install SQL Server Express with SQL Server Management Studio. That’s not a great thing, but it is one more nightmare step for users who may have other versions of SQL installed. Then the question became – do we detach and reattach or do we do a backup. It was too late (bad planning) to revert to Microsoft Access but we badly needed a simple way to package and distribute both the database AND sample contents. Red Gate to the rescue It took me a while to find an answer but I did find it in a package called SQL Packager sold by a relatively unpublicized company in England called Red Gate. They call their products “ingeniously simple” and I must agree with that description. With SQL Packager you point to the database (more in a minute) you want to distribute. A few mouse clicks and dialogs and you have an executable file that you can ship virtually anywhere and virtually any way which, when run, installs the database on your destination SQL Server instance! It really is that simple. Easier to show than tell Let’s explore a hypothetical case. Let’s say you have a local SQL database of customers and you have decided you want to share it with your subsidiaries or partners. Here is the underlying screen you will see on starting SQL Packager. There are a bunch of possibilities here but I’m going to keep this relatively simple. At this point I simply want to illustrate the simplicity of generating an executable to deliver your database. You will notice that you can set up a new package, edit an existing package or change a bunch of options. Start SQL packager And the following is the default dialog you get on startup. In the next dialog, I’ve selected the Server and Database. I’ve also selected Windows Authentication. Pressing Next causes SQL Packager to run a number of checks and produce a report. Now you’re given a comprehensive list of what is going to be packaged and you’re allowed to change it if you desire. I’ve never made any changes here so I can’t really make any suggestions. The just illustrates the comprehensive nature of so many Red Gate products including this one. Clicking Next gives you still further options. SQL Packager then works its magic and shows you a dialog with the results. Packager then gives you a dialog of the scripts it has generated. The capture above only shows 1 of 4 tabs. Finally pressing Next gives you the option to generate a .NET executable of a C# project. I’ve only generated an executable so I’m not in a position to tell you what the C# project looks like. That may be the subject of further discussions. You can rename the package and tell SQL Packager where to save it. I’ve skipped a lot but this will serve to illustrate the comprehensive (and ingenious) things Red Gate does. All in all, it’s a superb way to distribute populated SQL databases. Oh – we’ll save running the resulting executable for later also but believe me it’s insanely simple.

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  • Need help with software licensing? Read on&hellip;

    - by juanlarios
    Figuring out which software licensing options best suit your needs while being cost-effective can be confusing. Some businesses end up making their purchases through retail stores which means they miss out on volume licensing opportunities and others may unknowingly be using unlicensed software which means their business may be at risk. So let me help you make the best decision for your situation. You may want to review this blog post that lays out licensing basics for any organization that needs to license software for more than 5 or less than 250 devices or users. It details the different ways you can buy a license and what choices are available for volume licensing, which can give you pricing advantages and provide flexible options for your business. As technology evolves and more organizations move to online services such as Microsoft Office 365, Microsoft Dynamics CRM Online, Windows Azure Platform, Windows Intune and others, it’s important to understand how to purchase, activate and use online service subscriptions to get the most out of your investment. Once purchased through a volume licensing agreement or the Microsoft Online Subscription Program, these services can be managed through web portals: · Online Services Customer Portal (Microsoft Office 365, Microsoft Intune) · Dynamics CRM Online Customer Portal (Microsoft Dynamics CRM Online) · Windows Azure Customer Portal (Windows Azure Platform) · Volume Licensing Service Center (other services) Learn more >> Licensing Resources: The SMB How to Buy Portal – receive clear purchasing and licensing information that is easy to understand in order to help facilitate quick decision making. Microsoft License Advisor (MLA) – Use MLA to research Microsoft Volume Licensing products, programs and pricing. Volume Licensing Service Center (VLSC) – Already have a volume License? Use the VLSC to get you easy access to all your licensing information in one location. Online Services – licensing information for off-premise options. Windows 7 Comparison: – Compare versions of Windows and find out which one is right for you. Office 2010 Comparison: – Find out which Office suite is right for you. Licensing FAQs – Frequently Asked Questions About Product Licensing. Additional Resources You May Find Useful: · TechNet Evaluation Center Try some of our latest Microsoft products For free, Like System Center 2012 Pre-Release Products, and evaluate them before you buy. · Springboard Series Your destination for technical resources, free tools and expert guidance to ease the deployment and management of your Windows-based client infrastructure.   · AlignIT Manager Tech Talk Series A monthly streamed video series with a range of topics for both infrastructure and development managers.  Ask questions and participate real-time or watch the on-demand recording.

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  • Getting Started with Cloud Computing

    - by juanlarios
    You’ve likely heard about how Office 365 and Windows Intune are great applications to get you started with Cloud Computing. Many of you emailed me asking for more info on what Cloud Computing is, including the distinction between "Public Cloud" and "Private Cloud". I want to address these questions and help you get started. Let's begin with a brief set of definitions and some places to find more info; however, an excellent place where you can always learn more about Cloud Computing is the Microsoft Virtual Academy. Public Cloud computing means that the infrastructure to run and manage the applications users are taking advantage of is run by someone else and not you. In other words, you do not buy the hardware or software to run your email or other services being used in your organization – that is done by someone else. Users simply connect to these services from their computers and you pay a monthly subscription fee for each user that is taking advantage of the service. Examples of Public Cloud services include Office 365, Windows Intune, Microsoft Dynamics CRM Online, Hotmail, and others. Private Cloud computing generally means that the hardware and software to run services used by your organization is run on your premises, with the ability for business groups to self-provision the services they need based on rules established by the IT department. Generally, Private Cloud implementations today are found in larger organizations but they are also viable for small and medium-sized businesses since they generally allow an automation of services and reduction in IT workloads when properly implemented. Having the right management tools, like System Center 2012, to implement and operate Private Cloud is important in order to be successful. So – how do you get started? The first step is to determine what makes the most sense to your organization. The nice thing is that you do not need to pick Public or Private Cloud – you can use elements of both where it makes sense for your business – the choice is yours. When you are ready to try and purchase Public Cloud technologies, the Microsoft Volume Licensing web site is a good place to find links to each of the online services. In particular, if you are interested in a trial for each service, you can visit the following pages: Office 365, CRM Online, Windows Intune, and Windows Azure. For Private Cloud technologies, start with some of the courses on Microsoft Virtual Academy and then download and install the Microsoft Private Cloud technologies including Windows Server 2008 R2 Hyper-V and System Center 2012 in your own environment and take it for a spin. Also, keep up to date with the Canadian IT Pro blog to learn about events Microsoft is delivering such as the IT Virtualization Boot Camps and more to get you started with these technologies hands on. Finally, I want to ask for your help to allow the team at Microsoft to continue to provide you what you need. Twice a year through something we call "The Global Relationship Study" – they reach out and contact you to see how they're doing and what Microsoft could do better. If you get an email from "Microsoft Feedback" with the subject line "Help Microsoft Focus on Customers and Partners" between March 5th and April 13th, please take a little time to tell them what you think. Cloud Computing Resources: Microsoft Server and Cloud Computing site – information on Microsoft's overall cloud strategy and products. Microsoft Virtual Academy – for free online training to help improve your IT skillset. Office 365 Trial/Info page – get more information or try it out for yourself. Office 365 Videos – see how businesses like yours have used Office 365 to transition to the cloud. Windows Intune Trial/Info – get more information or try it out for yourself. Microsoft Dynamics CRM Online page – information on trying and licensing Microsoft Dynamics CRM Online. Additional Resources You May Find Useful: Springboard Series Your destination for technical resources, free tools and expert guidance to ease the deployment and management of your Windows-based client infrastructure. TechNet Evaluation Center Try some of our latest Microsoft products for free, Like System Center 2012 Pre-Release Products, and evaluate them before you buy. AlignIT Manager Tech Talk Series A monthly streamed video series with a range of topics for both infrastructure and development managers. Ask questions and participate real-time or watch the on-demand recording. Tech·Days Online Discover what's next in technology and innovation with Tech·Days session recordings, hands-on labs and Tech·Days TV.

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  • It&rsquo;s About You: Tell Microsoft How They&rsquo;re Doing!

    - by juanlarios
    Every fall and spring, a survey goes out to a few hundred thousand IT folk in Canada asking what they think of Microsoft as a company. The information they get from this survey helps them understand what problems and issues you’re facing and how they can do better. The team at Microsoft Canada takes the input they get from this survey very seriously. Now I don’t know who of you will get the survey and who won’t but if you do find an email in your inbox from "Microsoft Feedback” with an email address of “ [email protected] ” and a subject line “Help Microsoft Focus on Customers and Partners” from now until April 13th — it’s not a hoax or phishing email. Please open it and take a few minutes to tell them what you think. This is your chance to get your voice heard: If they’re doing well, feel free to pile on the kudos (they love positive feedback!) and if you see areas they can improve, please point them out so they can make adjustments (they also love constructive criticism!). The Microsoft team would like to thank you for all your feedback in the past — to those of you who have filled out the survey and sent them emails. Thank you to all who engage with them in so many different ways through events, the blogs, online and in person. You are why they do what they do and they feel lucky to work with such a great community! One last thing - even if you don’t get the survey you can always give the team feedback by emailing us directly through the Microsoft Canada IT Pro Feedback email address . They want to make sure they are serving you in the best possible way. Tell them what you want more of. What should they do less of or stop altogether? How can they help? Do you want more cowbell ? Let them know through the survey or the email alias. They love hearing from you!

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  • Organizations &amp; Architecture UNISA Studies &ndash; Chap 7

    - by MarkPearl
    Learning Outcomes Name different device categories Discuss the functions and structure of I/.O modules Describe the principles of Programmed I/O Describe the principles of Interrupt-driven I/O Describe the principles of DMA Discuss the evolution characteristic of I/O channels Describe different types of I/O interface Explain the principles of point-to-point and multipoint configurations Discuss the way in which a FireWire serial bus functions Discuss the principles of InfiniBand architecture External Devices An external device attaches to the computer by a link to an I/O module. The link is used to exchange control, status, and data between the I/O module and the external device. External devices can be classified into 3 categories… Human readable – e.g. video display Machine readable – e.g. magnetic disk Communications – e.g. wifi card I/O Modules An I/O module has two major functions… Interface to the processor and memory via the system bus or central switch Interface to one or more peripheral devices by tailored data links Module Functions The major functions or requirements for an I/O module fall into the following categories… Control and timing Processor communication Device communication Data buffering Error detection I/O function includes a control and timing requirement, to coordinate the flow of traffic between internal resources and external devices. Processor communication involves the following… Command decoding Data Status reporting Address recognition The I/O device must be able to perform device communication. This communication involves commands, status information, and data. An essential task of an I/O module is data buffering due to the relative slow speeds of most external devices. An I/O module is often responsible for error detection and for subsequently reporting errors to the processor. I/O Module Structure An I/O module functions to allow the processor to view a wide range of devices in a simple minded way. The I/O module may hide the details of timing, formats, and the electro mechanics of an external device so that the processor can function in terms of simple reads and write commands. An I/O channel/processor is an I/O module that takes on most of the detailed processing burden, presenting a high-level interface to the processor. There are 3 techniques are possible for I/O operations Programmed I/O Interrupt[t I/O DMA Access Programmed I/O When a processor is executing a program and encounters an instruction relating to I/O it executes that instruction by issuing a command to the appropriate I/O module. With programmed I/O, the I/O module will perform the requested action and then set the appropriate bits in the I/O status register. The I/O module takes no further actions to alert the processor. I/O Commands To execute an I/O related instruction, the processor issues an address, specifying the particular I/O module and external device, and an I/O command. There are four types of I/O commands that an I/O module may receive when it is addressed by a processor… Control – used to activate a peripheral and tell it what to do Test – Used to test various status conditions associated with an I/O module and its peripherals Read – Causes the I/O module to obtain an item of data from the peripheral and place it in an internal buffer Write – Causes the I/O module to take an item of data form the data bus and subsequently transmit that data item to the peripheral The main disadvantage of this technique is it is a time consuming process that keeps the processor busy needlessly I/O Instructions With programmed I/O there is a close correspondence between the I/O related instructions that the processor fetches from memory and the I/O commands that the processor issues to an I/O module to execute the instructions. Typically there will be many I/O devices connected through I/O modules to the system – each device is given a unique identifier or address – when the processor issues an I/O command, the command contains the address of the address of the desired device, thus each I/O module must interpret the address lines to determine if the command is for itself. When the processor, main memory and I/O share a common bus, two modes of addressing are possible… Memory mapped I/O Isolated I/O (for a detailed explanation read page 245 of book) The advantage of memory mapped I/O over isolated I/O is that it has a large repertoire of instructions that can be used, allowing more efficient programming. The disadvantage of memory mapped I/O over isolated I/O is that valuable memory address space is sued up. Interrupts driven I/O Interrupt driven I/O works as follows… The processor issues an I/O command to a module and then goes on to do some other useful work The I/O module will then interrupts the processor to request service when is is ready to exchange data with the processor The processor then executes the data transfer and then resumes its former processing Interrupt Processing The occurrence of an interrupt triggers a number of events, both in the processor hardware and in software. When an I/O device completes an I/O operations the following sequence of hardware events occurs… The device issues an interrupt signal to the processor The processor finishes execution of the current instruction before responding to the interrupt The processor tests for an interrupt – determines that there is one – and sends an acknowledgement signal to the device that issues the interrupt. The acknowledgement allows the device to remove its interrupt signal The processor now needs to prepare to transfer control to the interrupt routine. To begin, it needs to save information needed to resume the current program at the point of interrupt. The minimum information required is the status of the processor and the location of the next instruction to be executed. The processor now loads the program counter with the entry location of the interrupt-handling program that will respond to this interrupt. It also saves the values of the process registers because the Interrupt operation may modify these The interrupt handler processes the interrupt – this includes examination of status information relating to the I/O operation or other event that caused an interrupt When interrupt processing is complete, the saved register values are retrieved from the stack and restored to the registers Finally, the PSW and program counter values from the stack are restored. Design Issues Two design issues arise in implementing interrupt I/O Because there will be multiple I/O modules, how does the processor determine which device issued the interrupt? If multiple interrupts have occurred, how does the processor decide which one to process? Addressing device recognition, 4 general categories of techniques are in common use… Multiple interrupt lines Software poll Daisy chain Bus arbitration For a detailed explanation of these approaches read page 250 of the textbook. Interrupt driven I/O while more efficient than simple programmed I/O still requires the active intervention of the processor to transfer data between memory and an I/O module, and any data transfer must traverse a path through the processor. Thus is suffers from two inherent drawbacks… The I/O transfer rate is limited by the speed with which the processor can test and service a device The processor is tied up in managing an I/O transfer; a number of instructions must be executed for each I/O transfer Direct Memory Access When large volumes of data are to be moved, an efficient technique is direct memory access (DMA) DMA Function DMA involves an additional module on the system bus. The DMA module is capable of mimicking the processor and taking over control of the system from the processor. It needs to do this to transfer data to and from memory over the system bus. DMA must the bus only when the processor does not need it, or it must force the processor to suspend operation temporarily (most common – referred to as cycle stealing). When the processor wishes to read or write a block of data, it issues a command to the DMA module by sending to the DMA module the following information… Whether a read or write is requested using the read or write control line between the processor and the DMA module The address of the I/O device involved, communicated on the data lines The starting location in memory to read from or write to, communicated on the data lines and stored by the DMA module in its address register The number of words to be read or written, communicated via the data lines and stored in the data count register The processor then continues with other work, it delegates the I/O operation to the DMA module which transfers the entire block of data, one word at a time, directly to or from memory without going through the processor. When the transfer is complete, the DMA module sends an interrupt signal to the processor, this the processor is involved only at the beginning and end of the transfer. I/O Channels and Processors Characteristics of I/O Channels As one proceeds along the evolutionary path, more and more of the I/O function is performed without CPU involvement. The I/O channel represents an extension of the DMA concept. An I/O channel ahs the ability to execute I/O instructions, which gives it complete control over I/O operations. In a computer system with such devices, the CPU does not execute I/O instructions – such instructions are stored in main memory to be executed by a special purpose processor in the I/O channel itself. Two types of I/O channels are common A selector channel controls multiple high-speed devices. A multiplexor channel can handle I/O with multiple characters as fast as possible to multiple devices. The external interface: FireWire and InfiniBand Types of Interfaces One major characteristic of the interface is whether it is serial or parallel parallel interface – there are multiple lines connecting the I/O module and the peripheral, and multiple bits are transferred simultaneously serial interface – there is only one line used to transmit data, and bits must be transmitted one at a time With new generation serial interfaces, parallel interfaces are becoming less common. In either case, the I/O module must engage in a dialogue with the peripheral. In general terms the dialog may look as follows… The I/O module sends a control signal requesting permission to send data The peripheral acknowledges the request The I/O module transfers data The peripheral acknowledges receipt of data For a detailed explanation of FireWire and InfiniBand technology read page 264 – 270 of the textbook

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  • Organization &amp; Architecture UNISA Studies &ndash; Chap 13

    - by MarkPearl
    Learning Outcomes Explain the advantages of using a large number of registers Discuss the way in which compilers optimize register usage Discuss the evolution of CISC machines Describe the characteristics of RISC architecture Discuss the RISC vs. CISC controversy Describe the way in which RISC and CISC design principles can be combined Instruction Execution Characteristics To understand the the line of reasoning of RISC advocates, we need a brief overview of instruction execution characteristics. These include… Operations Operands Procedure Calls These three sections can be studied in depth in the textbook at pages 503 - 505 A number of groups have come up with the conclusion that the attempt to make the instruction set architecture closer to HLLs (High Level Languages) is not the most effective design strategy. Rather HLL’s can be best supported by optimizing performance of the most time-consuming features of typical HLL programs. Generally 3 main characteristics came up to improve performance… Use a large number of registers or use a compiler to optimize register usage Careful attention needs to be paid to the design of instruction pipelines A simplified (reduced) instruction set is indicated The use of a large register optimization One of the most important design principles of RISC machines is the use of a large number of registers. The concept of register windows and the use of a large register file versus the use of cache memory are discussed. On the face of it, the use of a large set of registers should decrease the need to access memory. The design task is to organize the registers in such a fashion that this goal is realized. Read page 507 – 510 for a detailed explanation. Compiler-based register optimization   Reduced Instructions Set Architecture There are two advantages to smaller programs… Because the program takes up less memory, there is a savings in that resource (this was more compelling when memory was more expensive) Smaller programs should improve performance, and this will happen in two ways – fewer instructions means fewer instruction bytes to be fetched and in a paging environment smaller programs occupy fewer pages, reducing page faults. Certain characteristics are common to RISC processors… One instruction per cycle Register-to-register operations Simple addressing modes Simple instruction formats RISC vs. CISC After initial enthusiasm for RISC machines, there has been a growing realization that RISC designs may benefit from the inclusion of some CISC features CISC designs may benefit from the inclusion of some RISC features

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  • Fix a jQuery/HTML5 dynamic content issue by upgrading jQuery

    - by Steve Albers
    The default NuGet template for MVC3 pushes down jQuery 1.5.1.  You can upgrade to a new version (1.7.1 is current when this is written) to avoid a problem with the creation of “unknown” HTML5 tags in IE6-8: Take this sample HTML page using HTML5Shiv to provide support for new HTML5 tags in IE6 – IE8.  The page has a number of <article> tags that are backwards compatible in Internet Explorer 6-8 thanks to the HTML5Shiv. After the article elements there is a jQuery 1.5.1 script tag, and a ready() event handler that appends a footer element with a copyright to each of the article tags.  This appears correctly in IE9, but in older IE browsers the unknown tag problem reappears for the dynamic <footer> elements, even though we have the HTML5Shiv at the top of the page.  The copyright text sits outside of the two separate footer tags. To solve the issue upgrade your jQuery files to an up-to-date version.  For instance in Visual Studio 2010: In the Solution Explorer right click on References and choose Manage NuGet Packages. In the Manage NuGet Packages window select the jQuery item on the middle of the page and click the “Upgrade” button. You may need to upgrade your script src references to point at the new version. Using the updated jQuery library the incorrect tags should disappear and styles should work properly:   You can find more information about the issue on the jQuery Bug Tracker site.

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