The major change is to upgrade the relevant references to the latest version (4.0 /2.0). You need to update your web config files to upgrade the version of the following namespaces

   - System.Web.Mvc ( Change to 4.0.0.0) 
   - System.Web.Webpages (Change to 2.0.0.0) 
   - System.Web.Helpers (Change to 2.0.0.0)
   - System.Web.WebPages.Razor (Change to 2.0.0.0)

Also you need to update the root level web config file to have these appsettings entries

    &lt;appSettings&gt;
      &lt;add key=&quot;webpages:Version&quot; value=&quot;2.0.0.0&quot; /&gt;
      &lt;add key=&quot;PreserveLoginUrl&quot; value=&quot;true&quot; /&gt;
    &lt;/appSettings&gt;

Then you need to update the DLLs referenced in the project. Remove the existing MVC3 dll reference and add MVC4 (use nuget package manager to do this)

This [link][1] handles all aspects of the conversion. Refer it as needed.


  


  [1]: https://docs.microsoft.com/en-us/aspnet/whitepapers/mvc4-release-notes#upgrading-an-aspnet-mvc-3-project-to-aspnet-mvc-4

Follow the official steps posted here:

[Upgrading an ASP.NET MVC 3 Project to ASP.NET MVC 4](https://docs.microsoft.com/en-us/aspnet/whitepapers/mvc4-release-notes#upgrading-an-aspnet-mvc-3-project-to-aspnet-mvc-4)

Note: These steps cover the official release--not the developer preview.

Better yet, use the auto-update tool:

https://www.nuget.org/packages/UpgradeMvc3ToMvc4

Your best bet it&#39;s installing the MVC4 from the platform installer.
Then follow the steps on the official asp.net/mvc/mvc4 page. If you follow (only) the Shyju instructions It wouldn&#39;t work.

When you end with the official instructions, look on your Views directory, and you may find another web.config with another reference to the MVC assembly and several others for razor.
You also want to change the versions of this lines. Basically replace every 3.0.0.0 you find for 4.0.0.0 and 1.0.0.0 for 2.0.0.0

IF YOU DON&#39;T MAKE THIS LAST CHANGE, YOU MAY END WITH THE ERROR ON THE FOLLOWING [QUESTION](https://stackoverflow.com/questions/9384421/installed-mvc-4-beta-now-my-mvc-3-projects-throw-an-error-when-i-rebuild-all)

Look for included dll&#39;s and make sure they&#39;re for the correct versions.

I am not sure what are the benefits of using `&lt;f:view&gt;` and `&lt;f:subview&gt;`.
I noticed that one could write JSF pages without using them.

What are the benefits of using those tags?



When to use f:view and f:subview

I&#39;m trying to install Hadoop on Ubuntu 11.10. I set the `JAVA_HOME` variable in the file `conf/hadoop-env.sh` to: 

    # export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

and then I execute these commands (Standalone Operation):

    $ mkdir input 
    $ cp conf/*.xml input 
    $ bin/hadoop jar hadoop-examples-*.jar grep input output &#39;dfs[a-z.]+&#39; 
    $ cat output/*

but I have the following error when executing the third command:

&gt; ERROR : JAVA_HOME is not set

Is the `JAVA_HOME` variable not set correctly?

Hadoop: &#171;ERROR : JAVA_HOME is not set&#187;

What steps should I take to safely upgrade an existing ASP.NET MVC 3 project to the latest ASP.NET MVC 4 [Developer Preview][1]?

  [1]: http://www.asp.net/mvc/mvc4

Converting a ASP.NET MVC 3 Project to MVC 4

<p>What steps should I take to safely upgrade an existing ASP.NET MVC 3 project to the latest ASP.NET MVC 4 <a href="http://www.asp.net/mvc/mvc4" target="_blank" rel="noopener noreferrer">Developer Preview</a>?</p>


I have sample code like this:
    
     &lt;div class=&quot;cart&quot;&gt;
          &lt;a onclick=&quot;addToCart(&#39;@Model.productId&#39;);&quot; class=&quot;button&quot;&gt;&lt;span&gt;Add to Cart&lt;/span&gt;&lt;/a&gt;
     &lt;/div&gt;
     &lt;div class=&quot;wishlist&quot;&gt;
          &lt;a onclick=&quot;addToWishList(&#39;@Model.productId&#39;);&quot;&gt;Add to Wish List&lt;/a&gt;
     &lt;/div&gt;
     &lt;div class=&quot;compare&quot;&gt;
          &lt;a onclick=&quot;addToCompare(&#39;@Model.productId&#39;);&quot;&gt;Add to Compare&lt;/a&gt;
     &lt;/div&gt;    
    
How can I write JavaScript code to call the controller action method?
   


Calling ASP.NET MVC Action Methods from JavaScript

I have following model:

    public class FormularModel
    {
        [Required]
        public string Position { get; set; }
        [Required]
        [DataType(DataType.EmailAddress)]
        public string Email { get; set; }
        [Required]
        public string Webcode { get; set; }
    }

Required validation works fine. But when i try with DataType it doesn&#39;t react.

Here is my razor code for the email control:
 

       @Html.TextBoxFor
              (model =&gt; model.Email, 
               new { @style = &quot;width: 175px;&quot;, @class = &quot;txtField&quot; }
              ) * 

So, anyone know an answer?

TIA

Email model validation with DataAnnotations and DataType

What is `routes.IgnoreRoute(&quot;{resource}.axd/{*pathInfo}&quot;)`

I cannot find any .axd file in my project, can I remove this route rule?

What is routes.IgnoreRoute(&quot;{resource}.axd/{*pathInfo}&quot;)

I have created an ASP.NET MVC 3 project, and am using IIS Express as the web server when developing. When I try to debug, I get the error message below.

How can this be solved?

&gt;Server Error in &#39;/&#39; Application.

&gt;Access is denied.
Description: An error occurred while accessing the resources required to serve this request. The server may not be configured for access to the requested URL.

&gt;Error message 401.2.: Unauthorized: Logon failed due to server configuration.  Verify that you have permission to view this directory or page based on the credentials you supplied and the authentication methods enabled on the Web server.  Contact the Web server&#39;s administrator for additional assistance.

IIS Express gives Access Denied error when debugging ASP.NET MVC

I have a piece of try catch code:

    try 
    {
        ...
    }
    catch(Exception ex) 
    {
        ModelState.AddModelError(
            &quot;duplicateInvoiceNumberOrganisation&quot;, &quot;The combination of organisation and invoice number must be unique&quot;);
    }

For this piece of code I&#39;m trying to insert a record into a database: The dba has set it up so that the database checks for duplicates and returns an error if there are duplicates. Currently, as you can see, I&#39;m adding the same error to the model no matter what error occurred. I want it changed so this error is only added to the model if it was caused by the duplicate error set up by the dba.

Below is the error I want to catch. Note it&#39;s in the inner exception. Can anyone tell me how to specifically catch this one?

![enter image description here][1]


  [1]: http://i.stack.imgur.com/LHMa3.jpg

How to determine if an exception is of a particular type

Imagine a common scenario, this is a simpler version of what I&#39;m coming across.  I actually have a couple of layers of further nesting on mine....

But this is the scenario

Theme contains List&lt;Category&gt;
Category contains List&lt;Product&gt;
Product contains List&lt;Order&gt;

My Controller provides a fully populated Theme, with all the Categories for that theme, the Products within this categories and the their orders.

The orders collection has a property called Quantity (amongst many others) that needs to be editable.

    @model ViewModels.MyViewModels.Theme
    
    @Html.LabelFor(Model.Theme.name)
    @foreach (var category in Model.Theme)
    {
       @Html.LabelFor(category.name)
       @foreach(var product in theme.Products)
       {
          @Html.LabelFor(product.name)
          @foreach(var order in product.Orders)
          {
              @Html.TextBoxFor(order.Quantity)
              @Html.TextAreaFor(order.Note)
              @Html.EditorFor(order.DateRequestedDeliveryFor)
          }
       }
    }

If I use lambda instead then then I only seem to get a reference to the top Model object, &quot;Theme&quot; not those within the foreach loop.


Is what I&#39;m trying to do there even possible or have I overestimated or misunderstood what is possible?

With the above I get an error on the TextboxFor, EditorFor, etc

&gt; CS0411: The type arguments for method
&gt; &#39;System.Web.Mvc.Html.InputExtensions.TextBoxFor&lt;TModel,TProperty&gt;(System.Web.Mvc.HtmlHelper&lt;TModel&gt;,
&gt; System.Linq.Expressions.Expression&lt;System.Func&lt;TModel,TProperty&gt;&gt;)&#39;
&gt; cannot be inferred from the usage. Try specifying the type arguments
&gt; explicitly.

Thanks.

MVC Razor view nested foreach&#39;s model

Embarrassingly newbie question:

I have a `string` field in my model that contains line breaks.  

    @Html.DisplayFor(x =&gt; x.MultiLineText)

does not display the line breaks.

Obviously I could do some fiddling in the model and create another field that replaces `\n` with `&lt;br/&gt;`, but that seems kludgy.  What&#39;s the textbook way to make this work?

How to make Html.DisplayFor display line breaks?

How do I access a key value from web.config in my Razor view.

This is in my `web.config` in the Web Project root level.

     &lt;appSettings&gt;
       &lt;add key=&quot;myKey&quot; value=&quot;MyValue&quot;/&gt;
    &lt;/appSettings&gt;

I want to have to use the key in my Razor view.

Thank you.




Access key value from Web.config in Razor View-MVC3 ASP.NET

*I realize this is a duplicate of about 20 different posts, but none of them are specific to MVC4, and none that I&#39;ve seen really answer all of my questions.* So far my first foray into the world of TDD has been frustrating to say the least. Most of what I&#39;ve tried to do seems incompatible with MVC 4 or next to impossible without using poorly documented third party libraries I don&#39;t quite understand yet.

What I want to be able to do, is write a tests that will test my Controller Actions, The Model they&#39;re passing and *The View* the action is sending the model to. I want to test if the view exists, I want to test if the model being passed is the right type for the view, I&#39;d like some way to test if it will process properly. I also want to be able to test my routes. And testing Authentication filters?

I want a way to unit test ASP.Net MVC that will leave very little to chance.

Testing the Model output of an Action seems easy enough, but testing the views has been next to impossible.

So here&#39;s my list of questions: 

 1. **Once I test the action and get the action result, how do I test to see if the view it wants exists?**
 2. **How do I test my routes?**
 3. **How can I test to be sure my views are being processed properly?**
 4. **What is really &quot;best practice&quot; for THOROUGH unit testing of ASP.Net MVC 4?**
 5. **How do I unit test forms authentication?**
 6. **How do I unit test Action Filters?**

I&#39;d prefer to use the built in Visual Studio test projects, but if I must use NUnit, I must. I just need to make sure it gets done properly.

Thank you in advance for your responses.

EDIT: I also couldn&#39;t get NUnit working with my MVC4 app because of some incompatibly with the version of .NET one of the assemblies was compiled in.

Unit Testing ASP.Net MVC 4 apps thoroughly

Steve Sanderson gave a very interesting presentations at Techdays 2012 in the Netherlands. In one of them [he presented](http://www.techdays.nl/AgendaDetail.aspx?cid=2159&amp;lang=en) a library that he used for client-server communication in MVC application: Upshot.

I was really amazed how easy it was to use it, so I wanted to download and test it. I found the download link here [through NuGet](http://nuget.org/packages/Upshot), but I cannot find any documentation. Does anyone have something that works? I would also appreciate the sample code that Steve showed as during presentation.

*EDIT:*

I found the online presentation I attended at Techdays. It&#39;s soooo much worth seeing. You will get a glance of what upshot is capable of and also get an idea how to start with it. Good luck and have fun.

The link: http://channel9.msdn.com/Events/TechDays/Techdays-2012-the-Netherlands/2159


Where can I find Upshot.js examples and documentation?

I get the following exception after installing ASP.NET MVC 4 Beta on a machine with ASP.NET MVC 3.

&gt;System.InvalidCastException was unhandled by user code
      Message=[A]System.Web.WebPages.Razor.Configuration.HostSection cannot be cast 
        to [B]System.Web.WebPages.Razor.Configuration.HostSection. Type A originates 
        from &#39;System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, 
        PublicKeyToken=31bf3856ad364e35&#39; in the context &#39;Default&#39; at location 
        &#39;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.WebPages.Razor\v4.0_1.0.0.0__31bf3856ad364e35\System.Web.WebPages.Razor.dll&#39;. 
        Type B originates from &#39;System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35&#39; 
        in the context &#39;Default&#39; at location &#39;C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.WebPages.Razor\v4.0_2.0.0.0__31bf3856ad364e35\System.Web.WebPages.Razor.dll&#39;.
      Source=System.Web.WebPages.Razor

&gt;StackTrace:

 &gt;at System.Web.WebPages.Razor.WebRazorHostFactory.GetRazorSection(String virtualPath)
       at System.Web.WebPages.Razor.WebRazorHostFactory.CreateHostFromConfig(String virtualPath, String physicalPath)
       at System.Web.WebPages.Razor.RazorBuildProvider.GetHostFromConfig()
       at System.Web.WebPages.Razor.RazorBuildProvider.CreateHost()
       at System.Web.WebPages.Razor.RazorBuildProvider.EnsureGeneratedCode()
       at System.Web.WebPages.Razor.RazorBuildProvider.get_CodeCompilerType()
       at System.Web.Compilation.BuildProvider.GetCompilerTypeFromBuildProvider(BuildProvider buildProvider)
       at System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders()
       at System.Web.Compilation.BuildProvidersCompiler.PerformBuild()
       at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath)
       at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
       at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
       at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound)
       at System.Web.Mvc.BuildManagerWrapper.System.Web.Mvc.IBuildManager.FileExists(String virtualPath)
       at System.Web.Mvc.BuildManagerViewEngine.FileExists(ControllerContext controllerContext, String virtualPath)
       at System.Web.Mvc.VirtualPathProviderViewEngine.GetPathFromGeneralName(ControllerContext controllerContext, List\`1 locations, String name, String controllerName, String areaName, String cacheKey, String[]&amp; searchedLocations)
       at System.Web.Mvc.VirtualPathProviderViewEngine.GetPath(ControllerContext controllerContext, String[] locations, String[] areaLocations, String locationsPropertyName, String name, String controllerName, String cacheKeyPrefix, Boolean useCache, String[]&amp; searchedLocations)
       at System.Web.Mvc.VirtualPathProviderViewEngine.FindView(ControllerContext controllerContext, String viewName, String masterName, Boolean useCache)
       at System.Web.Mvc.ViewEngineCollection.&lt;&gt;c__DisplayClassc.&lt;FindView&gt;b__b(IViewEngine e)
       at System.Web.Mvc.ViewEngineCollection.Find(Func\`2 lookup, Boolean trackSearchedPaths)
       at System.Web.Mvc.ViewEngineCollection.FindView(ControllerContext controllerContext, String viewName, String masterName)
       at System.Web.Mvc.ViewResult.FindView(ControllerContext context)
       at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
       at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult)
       at System.Web.Mvc.ControllerActionInvoker.&lt;&gt;c__DisplayClass1c.&lt;InvokeActionResultWithFilters&gt;b__19()
       at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func\`1 continuation)
       at System.Web.Mvc.ControllerActionInvoker.&lt;&gt;c__DisplayClass1c.&lt;&gt;c__DisplayClass1e.&lt;InvokeActionResultWithFilters&gt;b__1b()
       at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList\`1 filters, ActionResult actionResult)
       at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)
       at System.Web.Mvc.Controller.ExecuteCore()
       at [project_namespace].Controllers.GlobalizationController.ExecuteCore() in [file_path]
       at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext)
       at System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext)
       at System.Web.Mvc.MvcHandler.&lt;&gt;c__DisplayClass6.&lt;&gt;c__DisplayClassb.&lt;BeginProcessRequest&gt;b__5()
       at System.Web.Mvc.Async.AsyncResultWrapper.&lt;&gt;c__DisplayClass1.&lt;MakeVoidDelegate&gt;b__0()
       at System.Web.Mvc.Async.AsyncResultWrapper.&lt;&gt;c__DisplayClass8\`1.&lt;BeginSynchronous&gt;b__7(IAsyncResult _)
       at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult\`1.End()
       at System.Web.Mvc.MvcHandler.&lt;&gt;c__DisplayClasse.&lt;EndProcessRequest&gt;b__d()
       at System.Web.Mvc.SecurityUtil.&lt;GetCallInAppTrustThunk&gt;b__0(Action f)
       at System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action)
       at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
       at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result)
       at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
       at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&amp; completedSynchronously)

This blocks me completely and while I would like to keep the beta, I might need to remove it completely in order to get rid of the exception.

InvalidCastException is thrown after installing ASP.NET MVC 4 Beta

I am working on creating a new set of services in ASP.MVC MVC 4 using the Web API.  So far, it&#39;s great.  I have created the service and gotten it to work, and now I am trying to consume it using JQuery.  I can get back the JSON string using Fiddler, and it seems to be ok, but because the service exists on a separate site, trying to call it with JQuery errors with the &quot;Not Allowed&quot;.  So, this is clearly a case where I need to use JSONP.

I know that the Web API is new, but I&#39;m hoping someone out there can help me.

How do I make a call to a Web API method using JSONP?

JSONP with ASP.NET Web API

I have a bit of a weird problem.   
I developed an app with MVC 4 and the new Web API and it works fine locally. 
I installed MVC4 on the server and deployed the app. Now I get the following error:

&gt; Could not load file or assembly &#39;System.Net.Http, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35&#39; or one of its dependencies. The located assembly&#39;s manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)       
&gt;
&gt; Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in

Funny enough, the version of System.Net.Http that I locally have either in my package folder or in the ASP.NET MVC 4\Assemblies folder is 1.0.0.0. 
I actually removed the reference to System.Net.Http from my project, but I still get the same message. I&#39;m a bit confused about where it gets the 2.0.0.0 reference from and why it would work locally but not on the server.

Looking at the nuget dependencies:

ASP.NET WEb API Core Libraries (Beta) depends on System.Net.Http.Formatting.   
And System.Net.Http.Formatting depends on System.Net.Http.  
I guess that is where this comes from. But I do have Version 2.0.20126.16343 of this package installed, it&#39;s just that the dll inside has version 1.0.0.0  

Am I missing something?

**UPDATE:**

This is a sub-application of another ASP.NET app, but the other one is still based on WebForms. So, something is getting messed up. But if I do a clean under the assembly section in the web.config if does not even find the app itself anymore.


Content Type	Original Author	Original Content on Stackoverflow
Question	Petrus Theron	View Question on Stackoverflow
Solution 1 - asp.net Mvc	Shyju	View Answer on Stackoverflow
Solution 2 - asp.net Mvc	Seth	View Answer on Stackoverflow
Solution 3 - asp.net Mvc	Justin	View Answer on Stackoverflow
Solution 4 - asp.net Mvc	Sergio	View Answer on Stackoverflow

Converting a ASP.NET MVC 3 Project to MVC 4

asp.net Mvc Problem Overview

asp.net Mvc Solutions

Solution 1 - asp.net Mvc

Solution 2 - asp.net Mvc

Solution 3 - asp.net Mvc

Solution 4 - asp.net Mvc

Hadoop: «ERROR : JAVA_HOME is not set»

When to use f:view and f:subview

Attributions