Could not load file or assembly System.Net.Http, Version=4.0.0.0 with ASP.NET (MVC 4) Web API OData Prerelease

Problem

After installing the Microsoft ASP.NET Web API OData package 5.0.0-rc1 prerelease I end up with the following exception:

Could not load file or assembly 'System.Web.Http, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

My MVC 4 project is brand new and really small, nothing fancy in it. I target .NET framework 4.5

I need this nuget package to implement PATCH using the Delta class (When I use the version 4.0.0.0 of the package, the Delta class is not working).

How can I fix that?

My versions of System.Web.Http

In GAC I have version 5.0.0.0 of System.Web.Http

gacutil -l System.Web.Http The Global Assembly Cache contains the following assemblies: System.Web.Http, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL

In Visual Studio, when I browse assemblies, the given version of System.Web.Http is 4.0.0.0 (Why?)

In my project, the reference to System.Web.Http

• Has the version 5.0.0.0
• Points to the \lib\net45\ folder of the package
• Has CopyLocal=true

Things I tried

I tried to bind redirect v 4.0.0.0 to 5.0.0.0 in Web.config

<dependentAssembly>
    <assemblyIdentity name="System.Web.Http" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="4.0.0.0-4.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>

But it gives me another exception:

Attempt by method 'System.Web.Http.GlobalConfiguration..cctor()' to access field 'System.Web.Http.GlobalConfiguration.CS$<>9__CachedAnonymousMethodDelegate2' failed.

I guess that v 4.0.0.0 really need to be used by core Web Api engine.

Linked questions

Code Analysis error Could not load file or assembly 'System.Net.Http, Version=2.0.0.0 in MVC4 Web API Could not load file or assembly 'System.Net.Http, Version=2.0.0.0 in MVC4 Web API

Visual Studio 2013 has a new feature to take care of this. When you build the app, you should see warnings about different versions of an assembly being referenced. Double click the warning to add assembly binding redirects to the web.config.

See http://msdn.microsoft.com/en-us/library/2fc472t2.aspx for more details.

jeff.eynon notes below that you need to have the web.config checked out (if using TFS source control) to get VS to edit the file automatically. Thanks for the tip!

I made it work by upgrading the WebApi package to the prerelease version using nuget:

PM> Microsoft.AspNet.WebApi -Pre

In order to force the project using the latest version of WebApi, some modifications to the root Web.config were necessary:

1) Webpages Version from 2.0.0.0 to 3.0.0.0

<appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
</appSettings>

2) Binding redirect to 5.0.0.0 for System.Web.Http and System.Net.Http.Formatting

<dependentAssembly>
    <assemblyIdentity name="System.Web.Http" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>
<dependentAssembly>
    <assemblyIdentity name="System.Net.Http.Formatting" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>

I think that's it

PS: Solution highly inspired from WebAPI OData 5.0 Beta - Accessing GlobalConfiguration throws Security Error

I met the same problem and I resolved it by setting CopyLocal to true for the following libs:

System.Web.Http.dll
System.Web.Http.WebHost.dll
System.Net.Http.Formatting.dll

I must to add that I use MVC4 and NET 4

I experienced this issue when I tried to update a Hot Towel Project from the project template and when I created an empty project and installed HotTowel via nuget in VS 2012 as of 10/23/2013.

To fix, I updated via Nuget the Web Api Web Host and Web API packages to 5.0, the current version in NuGet at the moment (10/23/2013).

I then added the binding directs:

<dependentAssembly>
  <assemblyIdentity name="System.Web.Http" publicKeyToken="31bf3856ad364e35" culture="neutral" />
  <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>
<dependentAssembly>
  <assemblyIdentity name="System.Net.Http.Formatting" publicKeyToken="31bf3856ad364e35" culture="neutral" />
  <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
</dependentAssembly>