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• Custom built ASP.NET MVC2 breaks the strongly-typed views

  - by Petar Kabashki

  I have a problem with a custom built ASP.NET MVC2. The strongly-typed views break as the viewdata is treated as 'Object' instead of the corresponding type. The same views work perfectly with the default MVC2 from Microsoft.

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• Trouble with ASP.NET MVC auto-scaffolder template

  - by DanM

  I'm trying to write an auto-scaffolder template for Index views. I'd like to be able to pass in a collection of models or view-models (e.g., IQueryable<MyViewModel>) and get back an HTML table that uses the DisplayName attribute for the headings (th elements) and Html.Display(propertyName) for the cells (td elements). Each row should correspond to one item in the collection. Here's what I have so far: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl" %> <% var items = (IQueryable<TestProj.ViewModels.TestViewModel>)Model; // How do I make this generic? var properties = items.First().GetMetadata().Properties .Where(pm => pm.ShowForDisplay && !ViewData.TemplateInfo.Visited(pm)); %> <table> <tr> <% foreach(var property in properties) { %> <th> <%= property.DisplayName %> </th> <% } %> </tr> <% foreach(var item in items) { HtmlHelper itemHtml = ????; // What should I put in place of "????"? %> <tr> <% foreach(var property in properties) { %> <td> <%= itemHtml.Display(property.DisplayName) %> </td> <% } %> </tr> <% } %> </table> Two problems with this: I'd like it to be generic. So, I'd like to replace var items = (IQueryable<TestProj.ViewModels.TestViewModel>)Model; with var items = (IQueryable<T>)Model; or something to that effect. A property Html is automatically created for me when the view is created, but this HtmlHelper applies to the whole collection. I need to somehow create an itemHtml object that applies just to the current item in the foreach loop. I'm not sure how to do this, however, because the constructors for HtmlHelper don't take a Model object. How do I solve these two problems?

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• How to page multiple data sets in ASP.NET MVC

  - by REA_ANDREW

  On a single view I will have three sets of paged data. Which means for each model I will have The Objects The Page Index The Page Size My initial thought was for example: public class PagedModel<T> where T:class { public IList<T> Objects { get; set; } public int ModelPageIndex { get; set; } public int ModelPageSize { get; set; } } Then having a model which is to be supplied to the action as for example: public class TypesViewModel { public PagedModel<ObjectA> Types1 { get; set; } public PagedModel<ObjectB> Typed2 { get; set; } public PagedModel<ObjectC> Types3 { get; set; } } So if I then for example have the Index view inherit from the type: System.Web.Mvc.ViewPage<uk.co.andrewrea.forum.Web.Models.TypesViewModel> Now my initial aciton method for the index is simply: public ActionResult Index() { var forDisplayPurposes = new TypesViewModel(); return View(forDisplayPurposes); } If I then want to page, it is here where I am struggling to decide which action to take. Lets say that I select the next page of the Types2 PageModel. What should the action look like for this in order to return the new view showing the second page of the Types2 PageModel I was thinking possibly to duplicate the action but use it with POST [AcceptVerbs(HttpVerbs.Post)] public ActionResult Index(TypesViewModel model) { return View(model); } Is this a good way to approach it. I understand there is always Session, but I was just wondering how such a thing is achieved currently out there. If any best methods have been mutually accepted and things. So simply, one page with multiple paged models. How to persist the data for each using a wrapper model. Which way should you pass in the model and which way should you page the data, i.e. Form Post Lastly, I have seen the routes take this into account i.e. {controller}/{action}/{id}/{pageindex}/{pagesize} but this only accounts for one model and I do not really wwant to repeat the pagesize and pageindex values for the number of models I have inside the wrapper model. Thanks for your time!! Andrew

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• Capturing and Transforming ASP.NET Output with Response.Filter

  - by Rick Strahl

  During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic  GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT:  ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() {     HttpResponse Response = HttpContext.Current.Response;     if(IsGZipSupported())     {         stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"];         if(AcceptEncoding.Contains("deflate"))         {             Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter,                                        System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "deflate");         }         else        {             Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter,                                       System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "gzip");                            }     }     // Allow proxy servers to cache encoded and unencoded versions separately    Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a>  and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a>  without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable  component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• Running an intern program

  - by dotneteer

  This year I am running an unpaid internship program for high school students. I work for a small company. We have ideas for a few side projects but never have time to do them. So we experiment by making them intern projects. In return, we give these interns guidance to learn, personal attentions, and opportunities with real-world projects. A few years ago, I blogged about the idea of teaching kids to write application with no more than 6 hours of training. This time, I was able to reduce the instruction time to 4 hours and immediately put them into real work projects. When they encounter problems, I combine directions, pointer to various materials on w3school, Udacity, Codecademy and UTube, as well as encouraging them to  search for solutions with search engines. Now entering the third week, I am more than encouraged and feeling accomplished. Our the most senior intern, Christopher Chen, is a recent high school graduate and is heading to UC Berkeley to study computer science after the summer. He previously only had one year of Java experience through the AP computer science course but had no web development experience. Only 12 days into his internship, he has already gain advanced css skills with deeper understanding than more than half of the “senior” developers that I have ever worked with. I put him on a project to migrate an existing website to the Orchard content management system (CMS) with which I am new as well. We were able to teach each other and quickly gain advanced Orchard skills such as creating custom theme and modules. I felt very much a relationship similar to the those between professors and graduate students. On the other hand, I quite expect that I will lose him the next summer to companies like Google, Facebook or Microsoft. As a side note, Christopher and I will do a two part Orchard presentations together at the next SoCal code camp at UC San Diego July 27-28. The first part, “creating an Orchard website on Azure in 60 minutes”, is an introductory lecture and we will discuss how to create a website using Orchard without writing code. The 2nd part, “customizing Orchard websites without limit”, is an advanced lecture and we will discuss custom theme and module development with WebMatrix and Visual Studio.

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• Creating a dynamic proxy generator with c# – Part 4 – Calling the base method

  - by SeanMcAlinden

  Creating a dynamic proxy generator with c# – Part 1 – Creating the Assembly builder, Module builder and caching mechanism Creating a dynamic proxy generator with c# – Part 2 – Interceptor Design Creating a dynamic proxy generator with c# – Part 3 – Creating the constructors   The plan for calling the base methods from the proxy is to create a private method for each overridden proxy method, this will allow the proxy to use a delegate to simply invoke the private method when required. Quite a few helper classes have been created to make this possible so as usual I would suggest download or viewing the code at http://rapidioc.codeplex.com/. In this post I’m just going to cover the main points for when creating methods. Getting the methods to override The first two notable methods are for getting the methods. private static MethodInfo[] GetMethodsToOverride<TBase>() where TBase : class {     return typeof(TBase).GetMethods().Where(x =>         !methodsToIgnore.Contains(x.Name) &&                              (x.Attributes & MethodAttributes.Final) == 0)         .ToArray(); } private static StringCollection GetMethodsToIgnore() {     return new StringCollection()     {         "ToString",         "GetHashCode",         "Equals",         "GetType"     }; } The GetMethodsToIgnore method string collection contains an array of methods that I don’t want to override. In the GetMethodsToOverride method, you’ll notice a binary AND which is basically saying not to include any methods marked final i.e. not virtual. Creating the MethodInfo for calling the base method This method should hopefully be fairly easy to follow, it’s only function is to create a MethodInfo which points to the correct base method, and with the correct parameters. private static MethodInfo CreateCallBaseMethodInfo<TBase>(MethodInfo method) where TBase : class {     Type[] baseMethodParameterTypes = ParameterHelper.GetParameterTypes(method, method.GetParameters());       return typeof(TBase).GetMethod(        method.Name,        BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,        null,        baseMethodParameterTypes,        null     ); }   /// <summary> /// Get the parameter types. /// </summary> /// <param name="method">The method.</param> /// <param name="parameters">The parameters.</param> public static Type[] GetParameterTypes(MethodInfo method, ParameterInfo[] parameters) {     Type[] parameterTypesList = Type.EmptyTypes;       if (parameters.Length > 0)     {         parameterTypesList = CreateParametersList(parameters);     }     return parameterTypesList; }   Creating the new private methods for calling the base method The following method outline how I’ve created the private methods for calling the base class method. private static MethodBuilder CreateCallBaseMethodBuilder(TypeBuilder typeBuilder, MethodInfo method) {     string callBaseSuffix = "GetBaseMethod";       if (method.IsGenericMethod || method.IsGenericMethodDefinition)     {                         return MethodHelper.SetUpGenericMethod             (                 typeBuilder,                 method,                 method.Name + callBaseSuffix,                 MethodAttributes.Private | MethodAttributes.HideBySig             );     }     else     {         return MethodHelper.SetupNonGenericMethod             (                 typeBuilder,                 method,                 method.Name + callBaseSuffix,                 MethodAttributes.Private | MethodAttributes.HideBySig             );     } } The CreateCallBaseMethodBuilder is the entry point method for creating the call base method. I’ve added a suffix to the base classes method name to keep it unique. Non Generic Methods Creating a non generic method is fairly simple public static MethodBuilder SetupNonGenericMethod(     TypeBuilder typeBuilder,     MethodInfo method,     string methodName,     MethodAttributes methodAttributes) {     ParameterInfo[] parameters = method.GetParameters();       Type[] parameterTypes = ParameterHelper.GetParameterTypes(method, parameters);       Type returnType = method.ReturnType;       MethodBuilder methodBuilder = CreateMethodBuilder         (             typeBuilder,             method,             methodName,             methodAttributes,             parameterTypes,             returnType         );       ParameterHelper.SetUpParameters(parameterTypes, parameters, methodBuilder);       return methodBuilder; }   private static MethodBuilder CreateMethodBuilder (     TypeBuilder typeBuilder,     MethodInfo method,     string methodName,     MethodAttributes methodAttributes,     Type[] parameterTypes,     Type returnType ) { MethodBuilder methodBuilder = typeBuilder.DefineMethod(methodName, methodAttributes, returnType, parameterTypes); return methodBuilder; } As you can see, you simply have to declare a method builder, get the parameter types, and set the method attributes you want.   Generic Methods Creating generic methods takes a little bit more work. /// <summary> /// Sets up generic method. /// </summary> /// <param name="typeBuilder">The type builder.</param> /// <param name="method">The method.</param> /// <param name="methodName">Name of the method.</param> /// <param name="methodAttributes">The method attributes.</param> public static MethodBuilder SetUpGenericMethod     (         TypeBuilder typeBuilder,         MethodInfo method,         string methodName,         MethodAttributes methodAttributes     ) {     ParameterInfo[] parameters = method.GetParameters();       Type[] parameterTypes = ParameterHelper.GetParameterTypes(method, parameters);       MethodBuilder methodBuilder = typeBuilder.DefineMethod(methodName,         methodAttributes);       Type[] genericArguments = method.GetGenericArguments();       GenericTypeParameterBuilder[] genericTypeParameters =         GetGenericTypeParameters(methodBuilder, genericArguments);       ParameterHelper.SetUpParameterConstraints(parameterTypes, genericTypeParameters);       SetUpReturnType(method, methodBuilder, genericTypeParameters);       if (method.IsGenericMethod)     {         methodBuilder.MakeGenericMethod(genericArguments);     }       ParameterHelper.SetUpParameters(parameterTypes, parameters, methodBuilder);       return methodBuilder; }   private static GenericTypeParameterBuilder[] GetGenericTypeParameters     (         MethodBuilder methodBuilder,         Type[] genericArguments     ) {     return methodBuilder.DefineGenericParameters(GenericsHelper.GetArgumentNames(genericArguments)); }   private static void SetUpReturnType(MethodInfo method, MethodBuilder methodBuilder, GenericTypeParameterBuilder[] genericTypeParameters) {     if (method.IsGenericMethodDefinition)     {         SetUpGenericDefinitionReturnType(method, methodBuilder, genericTypeParameters);     }     else     {         methodBuilder.SetReturnType(method.ReturnType);     } }   private static void SetUpGenericDefinitionReturnType(MethodInfo method, MethodBuilder methodBuilder, GenericTypeParameterBuilder[] genericTypeParameters) {     if (method.ReturnType == null)     {         methodBuilder.SetReturnType(typeof(void));     }     else if (method.ReturnType.IsGenericType)     {         methodBuilder.SetReturnType(genericTypeParameters.Where             (x => x.Name == method.ReturnType.Name).First());     }     else     {         methodBuilder.SetReturnType(method.ReturnType);     }             } Ok, there are a few helper methods missing, basically there is way to much code to put in this post, take a look at the code at http://rapidioc.codeplex.com/ to follow it through completely. Basically though, when dealing with generics there is extra work to do in terms of getting the generic argument types setting up any generic parameter constraints setting up the return type setting up the method as a generic All of the information is easy to get via reflection from the MethodInfo.   Emitting the new private method Emitting the new private method is relatively simple as it’s only function is calling the base method and returning a result if the return type is not void. ILGenerator il = privateMethodBuilder.GetILGenerator();   EmitCallBaseMethod(method, callBaseMethod, il);   private static void EmitCallBaseMethod(MethodInfo method, MethodInfo callBaseMethod, ILGenerator il) {     int privateParameterCount = method.GetParameters().Length;       il.Emit(OpCodes.Ldarg_0);       if (privateParameterCount > 0)     {         for (int arg = 0; arg < privateParameterCount; arg++)         {             il.Emit(OpCodes.Ldarg_S, arg + 1);         }     }       il.Emit(OpCodes.Call, callBaseMethod);       il.Emit(OpCodes.Ret); } So in the main method building method, an ILGenerator is created from the method builder. The ILGenerator performs the following actions: Load the class (this) onto the stack using the hidden argument Ldarg_0. Create an argument on the stack for each of the method parameters (starting at 1 because 0 is the hidden argument) Call the base method using the Opcodes.Call code and the MethodInfo we created earlier. Call return on the method   Conclusion Now we have the private methods prepared for calling the base method, we have reached the last of the relatively easy part of the proxy building. Hopefully, it hasn’t been too hard to follow so far, there is a lot of code so I haven’t been able to post it all so please check it out at http://rapidioc.codeplex.com/. The next section should be up fairly soon, it’s going to cover creating the delegates for calling the private methods created in this post.   Kind Regards, Sean.

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• Creating a dynamic proxy generator with c# – Part 3 – Creating the constructors

  - by SeanMcAlinden

  Creating a dynamic proxy generator with c# – Part 1 – Creating the Assembly builder, Module builder and caching mechanism Creating a dynamic proxy generator with c# – Part 2 – Interceptor Design For the latest code go to http://rapidioc.codeplex.com/ When building our proxy type, the first thing we need to do is build the constructors. There needs to be a corresponding constructor for each constructor on the passed in base type. We also want to create a field to store the interceptors and construct this list within each constructor. So assuming the passed in base type is a User<int, IRepository> class, were looking to generate constructor code like the following:   Default Constructor public User`2_RapidDynamicBaseProxy() {     this.interceptors = new List<IInterceptor<User<int, IRepository>>>();     DefaultInterceptor<User<int, IRepository>> item = new DefaultInterceptor<User<int, IRepository>>();     this.interceptors.Add(item); }     Parameterised Constructor public User`2_RapidDynamicBaseProxy(IRepository repository1) : base(repository1) {     this.interceptors = new List<IInterceptor<User<int, IRepository>>>();     DefaultInterceptor<User<int, IRepository>> item = new DefaultInterceptor<User<int, IRepository>>();     this.interceptors.Add(item); }   As you can see, we first populate a field on the class with a new list of the passed in base type. Construct our DefaultInterceptor class. Add the DefaultInterceptor instance to our interceptor collection. Although this seems like a relatively small task, there is a fair amount of work require to get this going. Instead of going through every line of code – please download the latest from http://rapidioc.codeplex.com/ and debug through. In this post I’m going to concentrate on explaining how it works. TypeBuilder The TypeBuilder class is the main class used to create the type. You instantiate a new TypeBuilder using the assembly module we created in part 1. /// <summary> /// Creates a type builder. /// </summary> /// <typeparam name="TBase">The type of the base class to be proxied.</typeparam> public static TypeBuilder CreateTypeBuilder<TBase>() where TBase : class {     TypeBuilder typeBuilder = DynamicModuleCache.Get.DefineType         (             CreateTypeName<TBase>(),             TypeAttributes.Class | TypeAttributes.Public,             typeof(TBase),             new Type[] { typeof(IProxy) }         );       if (typeof(TBase).IsGenericType)     {         GenericsHelper.MakeGenericType(typeof(TBase), typeBuilder);     }       return typeBuilder; }   private static string CreateTypeName<TBase>() where TBase : class {     return string.Format("{0}_RapidDynamicBaseProxy", typeof(TBase).Name); } As you can see, I’ve create a new public class derived from TBase which also implements my IProxy interface, this is used later for adding interceptors. If the base type is generic, the following GenericsHelper.MakeGenericType method is called. GenericsHelper using System; using System.Reflection.Emit; namespace Rapid.DynamicProxy.Types.Helpers {     /// <summary>     /// Helper class for generic types and methods.     /// </summary>     internal static class GenericsHelper     {         /// <summary>         /// Makes the typeBuilder a generic.         /// </summary>         /// <param name="concrete">The concrete.</param>         /// <param name="typeBuilder">The type builder.</param>         public static void MakeGenericType(Type baseType, TypeBuilder typeBuilder)         {             Type[] genericArguments = baseType.GetGenericArguments();               string[] genericArgumentNames = GetArgumentNames(genericArguments);               GenericTypeParameterBuilder[] genericTypeParameterBuilder                 = typeBuilder.DefineGenericParameters(genericArgumentNames);               typeBuilder.MakeGenericType(genericTypeParameterBuilder);         }           /// <summary>         /// Gets the argument names from an array of generic argument types.         /// </summary>         /// <param name="genericArguments">The generic arguments.</param>         public static string[] GetArgumentNames(Type[] genericArguments)         {             string[] genericArgumentNames = new string[genericArguments.Length];               for (int i = 0; i < genericArguments.Length; i++)             {                 genericArgumentNames[i] = genericArguments[i].Name;             }               return genericArgumentNames;         }     } }       As you can see, I’m getting all of the generic argument types and names, creating a GenericTypeParameterBuilder and then using the typeBuilder to make the new type generic. InterceptorsField The interceptors field will store a List<IInterceptor<TBase>>. Fields are simple made using the FieldBuilder class. The following code demonstrates how to create the interceptor field. FieldBuilder interceptorsField = typeBuilder.DefineField(     "interceptors",     typeof(System.Collections.Generic.List<>).MakeGenericType(typeof(IInterceptor<TBase>)),       FieldAttributes.Private     ); The field will now exist with the new Type although it currently has no data – we’ll deal with this in the constructor. Add method for interceptorsField To enable us to add to the interceptorsField list, we are going to utilise the Add method that already exists within the System.Collections.Generic.List class. We still however have to create the methodInfo necessary to call the add method. This can be done similar to the following: Add Interceptor Field MethodInfo addInterceptor = typeof(List<>)     .MakeGenericType(new Type[] { typeof(IInterceptor<>).MakeGenericType(typeof(TBase)) })     .GetMethod     (        "Add",        BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,        null,        new Type[] { typeof(IInterceptor<>).MakeGenericType(typeof(TBase)) },        null     ); So we’ve create a List<IInterceptor<TBase>> type, then using the type created a method info called Add which accepts an IInterceptor<TBase>. Now in our constructor we can use this to call this.interceptors.Add(// interceptor); Building the Constructors This will be the first hard-core part of the proxy building process so I’m going to show the class and then try to explain what everything is doing. For a clear view, download the source from http://rapidioc.codeplex.com/, go to the test project and debug through the constructor building section. Anyway, here it is: DynamicConstructorBuilder using System; using System.Collections.Generic; using System.Reflection; using System.Reflection.Emit; using Rapid.DynamicProxy.Interception; using Rapid.DynamicProxy.Types.Helpers; namespace Rapid.DynamicProxy.Types.Constructors {     /// <summary>     /// Class for creating the proxy constructors.     /// </summary>     internal static class DynamicConstructorBuilder     {         /// <summary>         /// Builds the constructors.         /// </summary>         /// <typeparam name="TBase">The base type.</typeparam>         /// <param name="typeBuilder">The type builder.</param>         /// <param name="interceptorsField">The interceptors field.</param>         public static void BuildConstructors<TBase>             (                 TypeBuilder typeBuilder,                 FieldBuilder interceptorsField,                 MethodInfo addInterceptor             )             where TBase : class         {             ConstructorInfo interceptorsFieldConstructor = CreateInterceptorsFieldConstructor<TBase>();               ConstructorInfo defaultInterceptorConstructor = CreateDefaultInterceptorConstructor<TBase>();               ConstructorInfo[] constructors = typeof(TBase).GetConstructors();               foreach (ConstructorInfo constructorInfo in constructors)             {                 CreateConstructor<TBase>                     (                         typeBuilder,                         interceptorsField,                         interceptorsFieldConstructor,                         defaultInterceptorConstructor,                         addInterceptor,                         constructorInfo                     );             }         }           #region Private Methods           private static void CreateConstructor<TBase>             (                 TypeBuilder typeBuilder,                 FieldBuilder interceptorsField,                 ConstructorInfo interceptorsFieldConstructor,                 ConstructorInfo defaultInterceptorConstructor,                 MethodInfo AddDefaultInterceptor,                 ConstructorInfo constructorInfo             ) where TBase : class         {             Type[] parameterTypes = GetParameterTypes(constructorInfo);               ConstructorBuilder constructorBuilder = CreateConstructorBuilder(typeBuilder, parameterTypes);               ILGenerator cIL = constructorBuilder.GetILGenerator();               LocalBuilder defaultInterceptorMethodVariable =                 cIL.DeclareLocal(typeof(DefaultInterceptor<>).MakeGenericType(typeof(TBase)));               ConstructInterceptorsField(interceptorsField, interceptorsFieldConstructor, cIL);               ConstructDefaultInterceptor(defaultInterceptorConstructor, cIL, defaultInterceptorMethodVariable);               AddDefaultInterceptorToInterceptorsList                 (                     interceptorsField,                     AddDefaultInterceptor,                     cIL,                     defaultInterceptorMethodVariable                 );               CreateConstructor(constructorInfo, parameterTypes, cIL);         }           private static void CreateConstructor(ConstructorInfo constructorInfo, Type[] parameterTypes, ILGenerator cIL)         {             cIL.Emit(OpCodes.Ldarg_0);               if (parameterTypes.Length > 0)             {                 LoadParameterTypes(parameterTypes, cIL);             }               cIL.Emit(OpCodes.Call, constructorInfo);             cIL.Emit(OpCodes.Ret);         }           private static void LoadParameterTypes(Type[] parameterTypes, ILGenerator cIL)         {             for (int i = 1; i <= parameterTypes.Length; i++)             {                 cIL.Emit(OpCodes.Ldarg_S, i);             }         }           private static void AddDefaultInterceptorToInterceptorsList             (                 FieldBuilder interceptorsField,                 MethodInfo AddDefaultInterceptor,                 ILGenerator cIL,                 LocalBuilder defaultInterceptorMethodVariable             )         {             cIL.Emit(OpCodes.Ldarg_0);             cIL.Emit(OpCodes.Ldfld, interceptorsField);             cIL.Emit(OpCodes.Ldloc, defaultInterceptorMethodVariable);             cIL.Emit(OpCodes.Callvirt, AddDefaultInterceptor);         }           private static void ConstructDefaultInterceptor             (                 ConstructorInfo defaultInterceptorConstructor,                 ILGenerator cIL,                 LocalBuilder defaultInterceptorMethodVariable             )         {             cIL.Emit(OpCodes.Newobj, defaultInterceptorConstructor);             cIL.Emit(OpCodes.Stloc, defaultInterceptorMethodVariable);         }           private static void ConstructInterceptorsField             (                 FieldBuilder interceptorsField,                 ConstructorInfo interceptorsFieldConstructor,                 ILGenerator cIL             )         {             cIL.Emit(OpCodes.Ldarg_0);             cIL.Emit(OpCodes.Newobj, interceptorsFieldConstructor);             cIL.Emit(OpCodes.Stfld, interceptorsField);         }           private static ConstructorBuilder CreateConstructorBuilder(TypeBuilder typeBuilder, Type[] parameterTypes)         {             return typeBuilder.DefineConstructor                 (                     MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName                     | MethodAttributes.HideBySig, CallingConventions.Standard, parameterTypes                 );         }           private static Type[] GetParameterTypes(ConstructorInfo constructorInfo)         {             ParameterInfo[] parameterInfoArray = constructorInfo.GetParameters();               Type[] parameterTypes = new Type[parameterInfoArray.Length];               for (int p = 0; p < parameterInfoArray.Length; p++)             {                 parameterTypes[p] = parameterInfoArray[p].ParameterType;             }               return parameterTypes;         }           private static ConstructorInfo CreateInterceptorsFieldConstructor<TBase>() where TBase : class         {             return ConstructorHelper.CreateGenericConstructorInfo                 (                     typeof(List<>),                     new Type[] { typeof(IInterceptor<TBase>) },                     BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic                 );         }           private static ConstructorInfo CreateDefaultInterceptorConstructor<TBase>() where TBase : class         {             return ConstructorHelper.CreateGenericConstructorInfo                 (                     typeof(DefaultInterceptor<>),                     new Type[] { typeof(TBase) },                     BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic                 );         }           #endregion     } } So, the first two tasks within the class should be fairly clear, we are creating a ConstructorInfo for the interceptorField list and a ConstructorInfo for the DefaultConstructor, this is for instantiating them in each contructor. We then using Reflection get an array of all of the constructors in the base class, we then loop through the array and create a corresponding proxy contructor. Hopefully, the code is fairly easy to follow other than some new types and the dreaded Opcodes. ConstructorBuilder This class defines a new constructor on the type. ILGenerator The ILGenerator allows the use of Reflection.Emit to create the method body. LocalBuilder The local builder allows the storage of data in local variables within a method, in this case it’s the constructed DefaultInterceptor. Constructing the interceptors field The first bit of IL you’ll come across as you follow through the code is the following private method used for constructing the field list of interceptors. private static void ConstructInterceptorsField             (                 FieldBuilder interceptorsField,                 ConstructorInfo interceptorsFieldConstructor,                 ILGenerator cIL             )         {             cIL.Emit(OpCodes.Ldarg_0);             cIL.Emit(OpCodes.Newobj, interceptorsFieldConstructor);             cIL.Emit(OpCodes.Stfld, interceptorsField);         } The first thing to know about generating code using IL is that you are using a stack, if you want to use something, you need to push it up the stack etc. etc. OpCodes.ldArg_0 This opcode is a really interesting one, basically each method has a hidden first argument of the containing class instance (apart from static classes), constructors are no different. This is the reason you can use syntax like this.myField. So back to the method, as we want to instantiate the List in the interceptorsField, first we need to load the class instance onto the stack, we then load the new object (new List<TBase>) and finally we store it in the interceptorsField. Hopefully, that should follow easily enough in the method. In each constructor you would now have this.interceptors = new List<User<int, IRepository>>(); Constructing and storing the DefaultInterceptor The next bit of code we need to create is the constructed DefaultInterceptor. Firstly, we create a local builder to store the constructed type. Create a local builder LocalBuilder defaultInterceptorMethodVariable =     cIL.DeclareLocal(typeof(DefaultInterceptor<>).MakeGenericType(typeof(TBase))); Once our local builder is ready, we then need to construct the DefaultInterceptor<TBase> and store it in the variable. Connstruct DefaultInterceptor private static void ConstructDefaultInterceptor     (         ConstructorInfo defaultInterceptorConstructor,         ILGenerator cIL,         LocalBuilder defaultInterceptorMethodVariable     ) {     cIL.Emit(OpCodes.Newobj, defaultInterceptorConstructor);     cIL.Emit(OpCodes.Stloc, defaultInterceptorMethodVariable); } As you can see, using the ConstructorInfo named defaultInterceptorConstructor, we load the new object onto the stack. Then using the store local opcode (OpCodes.Stloc), we store the new object in the local builder named defaultInterceptorMethodVariable. Add the constructed DefaultInterceptor to the interceptors field collection Using the add method created earlier in this post, we are going to add the new DefaultInterceptor object to the interceptors field collection. Add Default Interceptor private static void AddDefaultInterceptorToInterceptorsList     (         FieldBuilder interceptorsField,         MethodInfo AddDefaultInterceptor,         ILGenerator cIL,         LocalBuilder defaultInterceptorMethodVariable     ) {     cIL.Emit(OpCodes.Ldarg_0);     cIL.Emit(OpCodes.Ldfld, interceptorsField);     cIL.Emit(OpCodes.Ldloc, defaultInterceptorMethodVariable);     cIL.Emit(OpCodes.Callvirt, AddDefaultInterceptor); } So, here’s whats going on. The class instance is first loaded onto the stack using the load argument at index 0 opcode (OpCodes.Ldarg_0) (remember the first arg is the hidden class instance). The interceptorsField is then loaded onto the stack using the load field opcode (OpCodes.Ldfld). We then load the DefaultInterceptor object we stored locally using the load local opcode (OpCodes.Ldloc). Then finally we call the AddDefaultInterceptor method using the call virtual opcode (Opcodes.Callvirt). Completing the constructor The last thing we need to do is complete the constructor. Complete the constructor private static void CreateConstructor(ConstructorInfo constructorInfo, Type[] parameterTypes, ILGenerator cIL)         {             cIL.Emit(OpCodes.Ldarg_0);               if (parameterTypes.Length > 0)             {                 LoadParameterTypes(parameterTypes, cIL);             }               cIL.Emit(OpCodes.Call, constructorInfo);             cIL.Emit(OpCodes.Ret);         }           private static void LoadParameterTypes(Type[] parameterTypes, ILGenerator cIL)         {             for (int i = 1; i <= parameterTypes.Length; i++)             {                 cIL.Emit(OpCodes.Ldarg_S, i);             }         } So, the first thing we do again is load the class instance using the load argument at index 0 opcode (OpCodes.Ldarg_0). We then load each parameter using OpCode.Ldarg_S, this opcode allows us to specify an index position for each argument. We then setup calling the base constructor using OpCodes.Call and the base constructors ConstructorInfo. Finally, all methods are required to return, even when they have a void return. As there are no values on the stack after the OpCodes.Call line, we can safely call the OpCode.Ret to give the constructor a void return. If there was a value, we would have to pop the value of the stack before calling return otherwise, the method would try and return a value. Conclusion This was a slightly hardcore post but hopefully it hasn’t been too hard to follow. The main thing is that a number of the really useful opcodes have been used and now the dynamic proxy is capable of being constructed. If you download the code and debug through the tests at http://rapidioc.codeplex.com/, you’ll be able to create proxies at this point, they cannon do anything in terms of interception but you can happily run the tests, call base methods and properties and also take a look at the created assembly in Reflector. Hope this is useful. The next post should be up soon, it will be covering creating the private methods for calling the base class methods and properties. Kind Regards, Sean.

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• ASP.NET Multipage TIFF Viewer with Thumbnails

  ASP.NET Multipage TIFF Viewer with Thumbnails

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• jQuery Ajax Error Handling – How To Show Custom Error Messages

  - by schnieds

  So you want to make your error feedback nice for your users…Kind of an ironic statement isn’t it? We obviously want to avoid errors if at all possible in our applications, but when errors do occur then we want to provide some nice feedback to our users. The worst thing that can happen is to blow up a huge server exception page when something goes wrong or equally bad is not providing any feedback at all and leaving the user in the dark. Although I do not recommend displaying actual .NET Framework exception messages or stack traces to the user in most instances; they are usually not helpful to the user and can be a security concern.... [Read More]Aaron Schniederhttp://www.churchofficeonline.com

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• RSS feeds in Orchard

  - by Latest Microsoft Blogs

  When we added RSS to Orchard , we wanted to make it easy for any module to expose any contents as a feed. We also wanted the rendering of the feed to be handled by Orchard in order to minimize the amount of work from the module developer. A typical example Read More......(read more)

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• DotNetQuiz 2011 on BeyondRelational.com- Want to be quiz master or participant?

  - by Jalpesh P. Vadgama

  Test your knowledge with 31 Reputed persons (MVPS and bloggers) will ask question on each day of January and you need to give reply on that. You can win cool stuff.My friend Jacob Sebastian organizing this event on his site Beyondrelational.com to sharpen your dot net related knowledge. This Dot NET Quiz is a platform to verify your understanding of Microsoft .NET Technologies and enhance your skills around it. This is a general quiz which covers most of the .NET technology areas. Want to be Quiz Master? Also if you are well known blogger or Microsoft MVP then you can be Quiz master on the dotnetquiz 2011. Following are requirements to be quiz master on beyondrelational.com. I am also a quiz master on beyondrelational.com and Quiz master eligibility: You will be eligible to nominate yourself to become a quiz master if one of the following condition satisfies: You are a Microsoft MVP You are a Former Microsoft MVP You are a recognized blogger You are a recognized web master running one or more technology websites You are an active participant of one or more technical forums You are a consultant with considerable exposure to your technology area You believe that you can be a good Quiz Master and got a passion for that   Selection Process: Once you submit your nomination, the Quiz team will evaluate the details and will inform you the status of your submission. This usually takes a few weeks. Quiz Master's Responsibilities: Once you become a Quiz Master for a specific quiz, you are requested to take the following responsibilities. Moderate the discussion thread after your question is published Answer any clarification about your question that people ask in the forum Review the answers and help us to award grades to the participants For more information Please visit following page on beyondrelational.com http://beyondrelational.com/quiz/nominations/0/new.aspx Hope you liked it. Stay tuned!!!

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• Writing C# Code Using SOLID Principles

  - by bipinjoshi

  Most of the modern programming languages including C# support objected oriented programming. Features such as encapsulation, inheritance, overloading and polymorphism are code level features. Using these features is just one part of the story. Equally important is to apply some object oriented design principles while writing your C# code. SOLID principles is a set of five such principles--namely Single Responsibility Principle, Open/Closed Principle, Liskov Substitution Principle, Interface Segregation Principle and Dependency Inversion Principle. Applying these time proven principles make your code structured, neat and easy to maintain. This article discusses SOLID principles and also illustrates how they can be applied to your C# code.http://www.binaryintellect.net/articles/7f857089-68f5-4d76-a3b7-57b898b6f4a8.aspx 

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• How to structure a XML-based order form using ASP.NET

  - by Brendan

  First question here; please help me if I'm doing something wrong. I'm a graphic designer who's trying to teach himself ASP.NET/C#. My server-side background is PHP/WordPress and some ASP Classic, and when I do code I've hand-coded just about everything since I started learning HTML. So, as I've started to learn .NET, my code has been very manual and procedural. I'm now trying to create a really basic order form that pulls from an XML file to populate the form; there's an image, a title, a price, and selectable quantities. If I was making this form as a static HTML file, I'd have each field named manually and so on postback I could query each field to get the values. But I'm trying to do this dynamically so that I can add/remove items from the form and not have to change the code. In terms of displaying the XML, I rolled my own by loading XmlDocument and using XmlNodeList and a bunch of foreach loops to get things displayed. Then, I learned about <asp:XmlDataSource> and <asp:Repeater>, which made displaying the XML simpler by a large margin. However, I've had a really hard time getting the data that's been submitted on postback (it was implied on SO that there are better ways to get data than nested RepeaterItems). So, what I've learned so far is that you can do things a bunch of different ways in .NET. that's why I thought it'd be good to ask for answers regarding the best way to use ASP.NET to display a XML document and dynamically capture the data that's submitted. Any help is appreciated! I'm using Notepad++ to code .NET 2.0.

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• Visual Studio 2010 Released

  - by Latest Microsoft Blogs

  It's a big day at Microsoft today as Visual Studio 2010 officially releases. There's a lot going on with this release and I thought I'd do a big rollup post with lots of details and context to help you find your way to the information and Read More......(read more)

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• Use IIS Application Initialization for keeping ASP.NET Apps alive

  - by Rick Strahl

  Ever want to run a service-like, always-on application inside of ASP.NET instead of creating a Windows Service or running a Console application? Need to make sure that your ASP.NET application is always running and comes up immediately after an Application Pool restart even if nobody hits your site? The IIS Application Initialization Module provides this functionality in IIS 7 and later, making it much easier to create always-on ASP.NET applications that can act like a service.

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• jQuery AJAX Validation Using The Validity Plugin

  - by schnieds

  Input validation is one of those areas that most developers view as a necessary evil. We know that it is necessary and we really do want to ensure that we get good input from our users. But most of us are lazy (me included) and input validation is one of those things that gets done but usually is a quick and dirty implementation. This is partly due to laziness and partly do to input validation being painful. Thanks to the amazing jQuery Validity plug in, input validation can be really slick, easy and robust enough to work any any scenario. I specifically like the Validity plugin because it supports jQuery AJAX input validation. Other input validation implementations that I have worked with require a form post to take place. However, if you are using jQuery.ajax methods then there isn’t a form and you need to validate the formless input. [Read More] Aaron Schniederhttp://www.churchofficeonline.com

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• Web Platform Installer 2.0 and Visual Studio Web Developer 2010 Express

  - by Latest Microsoft Blogs

  I was setting up a new machine for presentations and I was getting ready to install Visual Studio 2010 Express   and figured I'd go see if the Web Platform Installer (we call it "Web-P-I") had the new versions of VS2010 ready to go Read More......(read more)

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• Web Platform Installer 2.0 and Visual Studio Web Developer 2010 Express

  - by The Official Microsoft IIS Site

  I was setting up a new machine for presentations and I was getting ready to install Visual Studio 2010 Express   and figured I'd go see if the Web Platform Installer (we call it "Web-P-I") had the new versions of VS2010 ready to go. If you're not familiar, I've blogged about this before. WebPI is a 2meg download that basically sets up your machine for Web Development and downloads whatever you need automatically. It's a cafeteria plan for Microsoft Web Development....(read more)

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• New way of creating web applications on Visual Studio 2013

  - by DigiMortal

  Yesterday Visual Studio 2013 Preview was released and now it’s time to play with it. First thing I noticed was the new way how to create web applications. For all web applications there is generic dialog where you can set all important options for your new web application before it is created. Let’s see how it works. Also let’s take a look at new blue theme of Visual Studio 2013. Read more from my new blog @ gunnarpeipman.com

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• Caveats with the runAllManagedModulesForAllRequests in IIS 7/8

  - by Rick Strahl

  One of the nice enhancements in IIS 7 (and now 8) is the ability to be able to intercept non-managed - ie. non ASP.NET served - requests from within ASP.NET managed modules. This opened up a ton of new functionality that could be applied across non-managed content using .NET code. I thought I had a pretty good handle on how IIS 7's Integrated mode pipeline works, but when I put together some samples last tonight I realized that the way that managed and unmanaged requests fire into the pipeline is downright confusing especially when it comes to the runAllManagedModulesForAllRequests attribute. There are a number of settings that can affect whether a managed module receives non-ASP.NET content requests such as static files or requests from other frameworks like PHP or ASP classic, and this is topic of this blog post. Native and Managed Modules The integrated mode IIS pipeline for IIS 7 and later - as the name suggests - allows for integration of ASP.NET pipeline events in the IIS request pipeline. Natively IIS runs unmanaged code and there are a host of native mode modules that handle the core behavior of IIS. If you set up a new IIS site or application without managed code support only the native modules are supported and fired without any interaction between native and managed code. If you use the Integrated pipeline with managed code enabled however things get a little more confusing as there both native modules and .NET managed modules can fire against the same IIS request. If you open up the IIS Modules dialog you see both managed and unmanaged modules. Unmanaged modules point at physical files on disk, while unmanaged modules point at .NET types and files referenced from the GAC or the current project's BIN folder. Both native and managed modules can co-exist and execute side by side and on the same request. When running in IIS 7 the IIS pipeline actually instantiates a the ASP.NET  runtime (via the System.Web.PipelineRuntime class) which unlike the core HttpRuntime classes in ASP.NET receives notification callbacks when IIS integrated mode events fire. The IIS pipeline is smart enough to detect whether managed handlers are attached and if they're none these notifications don't fire, improving performance. The good news about all of this for .NET devs is that ASP.NET style modules can be used for just about every kind of IIS request. All you need to do is create a new Web Application and enable ASP.NET on it, and then attach managed handlers. Handlers can look at ASP.NET content (ie. ASPX pages, MVC, WebAPI etc. requests) as well as non-ASP.NET content including static content like HTML files, images, javascript and css resources etc. It's very cool that this capability has been surfaced. However, with that functionality comes a lot of responsibility. Because every request passes through the ASP.NET pipeline if managed modules (or handlers) are attached there are possible performance implications that come with it. Running through the ASP.NET pipeline does add some overhead. ASP.NET and Your Own Modules When you create a new ASP.NET project typically the Visual Studio templates create the modules section like this: <system.webServer> <validation validateIntegratedModeConfiguration="false" /> <modules runAllManagedModulesForAllRequests="true" > </modules> </system.webServer> Specifically the interesting thing about this is the runAllManagedModulesForAllRequest="true" flag, which seems to indicate that it controls whether any registered modules always run, even when the value is set to false. Realistically though this flag does not control whether managed code is fired for all requests or not. Rather it is an override for the preCondition flag on a particular handler. With the flag set to the default true setting, you can assume that pretty much every IIS request you receive ends up firing through your ASP.NET module pipeline and every module you have configured is accessed even by non-managed requests like static files. In other words, your module will have to handle all requests. Now so far so obvious. What's not quite so obvious is what happens when you set the runAllManagedModulesForAllRequest="false". You probably would expect that immediately the non-ASP.NET requests no longer get funnelled through the ASP.NET Module pipeline. But that's not what actually happens. For example, if I create a module like this:<add name="SharewareModule" type="HowAspNetWorks.SharewareMessageModule" /> by default it will fire against ALL requests regardless of the runAllManagedModulesForAllRequests flag. Even if the value runAllManagedModulesForAllRequests="false", the module is fired. Not quite expected. So what is the runAllManagedModulesForAllRequests really good for? It's essentially an override for managedHandler preCondition. If I declare my handler in web.config like this:<add name="SharewareModule" type="HowAspNetWorks.SharewareMessageModule" preCondition="managedHandler" /> and the runAllManagedModulesForAllRequests="false" my module only fires against managed requests. If I switch the flag to true, now my module ends up handling all IIS requests that are passed through from IIS. The moral of the story here is that if you intend to only look at ASP.NET content, you should always set the preCondition="managedHandler" attribute to ensure that only managed requests are fired on this module. But even if you do this, realize that runAllManagedModulesForAllRequests="true" can override this setting. runAllManagedModulesForAllRequests and Http Application Events Another place the runAllManagedModulesForAllRequest attribute affects is the Global Http Application object (typically in global.asax) and the Application_XXXX events that you can hook up there. So while the events there are dynamically hooked up to the application class, they basically behave as if they were set with the preCodition="managedHandler" configuration switch. The end result is that if you have runAllManagedModulesForAllRequests="true" you'll see every Http request passed through the Application_XXXX events, and you only see ASP.NET requests with the flag set to "false". What's all that mean? Configuring an application to handle requests for both ASP.NET and other content requests can be tricky especially if you need to mix modules that might require both. Couple of things are important to remember. If your module doesn't need to look at every request, by all means set a preCondition="managedHandler" on it. This will at least allow it to respond to the runAllManagedModulesForAllRequests="false" flag and then only process ASP.NET requests. Look really carefully to see whether you actually need runAllManagedModulesForAllRequests="true" in your applications as set by the default new project templates in Visual Studio. Part of the reason, this is the default because it was required for the initial versions of IIS 7 and ASP.NET 2 in order to handle MVC extensionless URLs. However, if you are running IIS 7 or later and .NET 4.0 you can use the ExtensionlessUrlHandler instead to allow you MVC functionality without requiring runAllManagedModulesForAllRequests="true": <handlers> <remove name="ExtensionlessUrlHandler-Integrated-4.0" /> <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" /> </handlers> Oddly this is the default for Visual Studio 2012 MVC template apps, so I'm not sure why the default template still adds runAllManagedModulesForAllRequests="true" is - it should be enabled only if there's a specific need to access non ASP.NET requests. As a side note, it's interesting that when you access a static HTML resource, you can actually write into the Response object and get the output to show, which is trippy. I haven't looked closely to see how this works - whether ASP.NET just fires directly into the native output stream or whether the static requests are re-routed directly through the ASP.NET pipeline once a managed code module is detected. This doesn't work for all non ASP.NET resources - for example, I can't do the same with ASP classic requests, but it makes for an interesting demo when injecting HTML content into a static HTML page :-) Note that on the original Windows Server 2008 and Vista (IIS 7.0) you might need a HotFix in order for ExtensionLessUrlHandler to work properly for MVC projects. On my live server I needed it (about 6 months ago), but others have observed that the latest service updates have integrated this functionality and the hotfix is not required. On IIS 7.5 and later I've not needed any patches for things to just work. Plan for non-ASP.NET Requests It's important to remember that if you write a .NET Module to run on IIS 7, there's no way for you to prevent non-ASP.NET requests from hitting your module. So make sure you plan to support requests to extensionless URLs, to static resources like files. Luckily ASP.NET creates a full Request and full Response object for you for non ASP.NET content. So even for static files and even for ASP classic for example, you can look at Request.FilePath or Request.ContentType (in post handler pipeline events) to determine what content you are dealing with. As always with Module design make sure you check for the conditions in your code that make the module applicable and if a filter fails immediately exit - minimize the code that runs if your module doesn't need to process the request.© Rick Strahl, West Wind Technologies, 2005-2012Posted in IIS7   ASP.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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• Encrypted Hidden Redux : Let's Get Salty

  - by HeartattacK

  In this article, Ashic Mahtab shows an elegant, reusable and unobtrusive way in which to persist sensitive data to the browser in hidden inputs and restoring them on postback without needing to change any code in controllers or actions. The approach is an improvement of his previous article and incorporates a per session salt during encryption. Note: Cross posted from Heartysoft.com. Permalink

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• An even better way to run T4MVC: a VS AddIn

  - by Latest Microsoft Blogs

  Last week, I blogged about a nice way of auto-running T4MVC by using the Macro IDE to write an OnBuildBegin event handler .  This was a big improvement over the hacky ‘AlwaysKeepTemplateDirty’ flag that we’ve been using since T4MVC’s early days. Read More......(read more)

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• T4MVC 2.6.13: now officially in MvcContrib, with a few new features

  - by Latest Microsoft Blogs

  To get the latest build of T4MVC: Go to MvcContrib T4MVC page on CodePlex   A few weeks back, we announced (mostly on Twitter) that T4MVC was moving into the MvcContrib Codeplex project.  I didn’t say much about it at the time because there Read More......(read more)

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• Newbie seeking advice on programming in general

  - by user974685

  need some of you to remember back to a time when you might have been bad at programming... Been at my new job (as a software developer) for a couple of months now, passed probation period. Have very little programming experience (C++ only) and am currently working with asp.net MVC and silverlight. So there's a website the company has been working on and I am joining the effort to make it better, iron out bugs etc. The problem is - learning about a system/website which has already been made, via visual studio. I ALWAYS feel HUGELY overwhelmed, never knowing which part of this line should I look up, and generally having lots of trouble getting the big picture. Visual studio itself is something I'm finding it difficult to get to grips with, let alone the asp.net framework. I get the impression that because my coworkers have more experience than me, they are getting all the good jobs, and I am left with crap to do - stuff which is not even vaguely programming. Meaning they are learning/creating more, and I am learning/creating near nothing. I'm getting demoralised, and too scared to say anything. I'm not stupid, I've read and practiced plenty of the fundamental programming concepts...I'm just bloody scared of this damn framework. I look at it and just feel paralyzed. The result is that I keep asking the older veteran guy of questions, and he is getting irritated, and would rather give me easy/mindless/non programming jobs to avoid wasting time with helping me out. Then when I don't understand something, I'm hesitating about whether or not I should ask him yet, and trying to decide if it would be a waste of time. I'm the kind of person who picks things up slowly, but with a lot of attention to detail. The former I think is making me look incompetent though. Anyone get where I'm coming from please say something helpful....I'm scared of losing my job in a few months or something...

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• Web Site Performance and Assembly Versioning

  - by capgpilk

  I originally wanted to write this post in one, but there is quite a large amount of information which can be broken down into different areas, so I am going to publish it in three posts. Minification and Concatination of JavaScript and CSS Files – this post Versioning Combined Files Using Subversion – published shortly Versioning Combined Files Using Mercurial – published shortly Website Performance There are many ways to improve web site performance, two areas are reducing the amount of data that is served up from the web server and reducing the number of files that are requested. Here I will outline the process of minimizing and concatenating your javascript and css files automatically at build time of your visual studio web site/ application. To edit the project file in Visual Studio, you need to first unload it by right clicking the project in Solution Explorer. I prefer to do this in a third party tool such as Notepad++ and save it there forcing VS to reload it each time I make a change as the whole process in Visual Studio can be a bit tedious. Now you have the project file, you will notice that it is an MSBuild project file. I am going to use a fantastic utility from Microsoft called Ajax Minifier. This tool minifies both javascript and css. 1. Import the tasks for AjaxMin choosing the location you installed to. I keep all third party utilities in a Tools directory within my solution structure and source control. This way I know I can get the entire solution from source control without worrying about what other tools I need to get the project to build locally. 1: <Import Project="..\Tools\MicrosoftAjaxMinifier\AjaxMin.tasks" /> 2. Now create ItemGroups for all your js and css files like this. Separating out your non minified files and minified files. This can go in the AfterBuild container. 1: <Target Name="AfterBuild"> 2:  3: <!-- Javascript files that need minimizing --> 4: <ItemGroup> 5: <JSMin Include="Scripts\jqModal.js" /> 6: <JSMin Include="Scripts\jquery.jcarousel.js" /> 7: <JSMin Include="Scripts\shadowbox.js" /> 8: </ItemGroup> 9: <!-- CSS files that need minimizing --> 10: <ItemGroup> 11: <CSSMin Include="Content\Site.css" /> 12: <CSSMin Include="Content\themes\base\jquery-ui.css" /> 13: <CSSMin Include="Content\shadowbox.css" /> 14: </ItemGroup>   1: <!-- Javascript files to combine --> 2: <ItemGroup> 3: <JSCat Include="Scripts\jqModal.min.js" /> 4: <JSCat Include="Scripts\jquery.jcarousel.min.js" /> 5: <JSCat Include="Scripts\shadowbox.min.js" /> 6: </ItemGroup> 7: <!-- CSS files to combine --> 8: <ItemGroup> 9: <CSSCat Include="Content\Site.min.css" /> 10: <CSSCat Include="Content\themes\base\jquery-ui.min.css" /> 11: <CSSCat Include="Content\shadowbox.min.css" /> 12: </ItemGroup>   3. Call AjaxMin to do the crunching. 1: <Message Text="Minimizing JS and CSS Files..." Importance="High" /> 2: <AjaxMin JsSourceFiles="@(JSMin)" JsSourceExtensionPattern="\.js$" 3: JsTargetExtension=".min.js" JsEvalTreatment="MakeImmediateSafe" 4: CssSourceFiles="@(CSSMin)" CssSourceExtensionPattern="\.css$" 5: CssTargetExtension=".min.css" /> This will create the *.min.css and *.min.js files in the same directory the original files were. 4. Now concatenate the minified files into one for javascript and another for css. Here we write out the files with a default file name. In later posts I will cover versioning these files the same as your project assembly again to help performance. 1: <Message Text="Concat JS Files..." Importance="High" /> 2: <ReadLinesFromFile File="%(JSCat.Identity)"> 3: <Output TaskParameter="Lines" ItemName="JSLinesSite" /> 4: </ReadLinesFromFile> 5: <WriteLinestoFile File="Scripts\site-script.combined.min.js" Lines="@(JSLinesSite)" 6: Overwrite="true" /> 7: <Message Text="Concat CSS Files..." Importance="High" /> 8: <ReadLinesFromFile File="%(CSSCat.Identity)"> 9: <Output TaskParameter="Lines" ItemName="CSSLinesSite" /> 10: </ReadLinesFromFile> 11: <WriteLinestoFile File="Content\site-style.combined.min.css" Lines="@(CSSLinesSite)" 12: Overwrite="true" /> 5. Save the project file, if you have Visual Studio open it will ask you to reload the project. You can now run a build and these minified and combined files will be created automatically. 6. Finally reference these minified combined files in your web page. In the next two posts I will cover versioning these files to match your assembly.

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