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

Solution 1:

I had the same error while deploying previously converted (from .NET 4.5 to 4.0) web app on IIS 6.0.

In the web.config runtime section I've found

<dependentAssembly>
    <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
    <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
</dependentAssembly>

which I've changed to

<dependentAssembly>
    <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
    <bindingRedirect oldVersion="0.0.0.0-1.0.0.0" newVersion="2.0.0.0"/>
</dependentAssembly>

Now works like charm.

Solution 2:

I had the same problem with deployment my app to appharbor. The problem it does not support .NET 4.5 yet. What I did.

1. Switched my project to .NET 4.0 profile.
2. Uninstalled Web API NuGet package.
3. Installed Web API (Beta) NuGet package again.
4. Verified that .csproj file contains for ALL referenced assemblies, so it will always take it from Bin folder, instead of GAC.

Solution 3:

Mine worked with:

Note the redirect of 1-4 to 2.0

<dependentAssembly>
    <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a"   culture="neutral"/>
    <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="2.0.0.0"/>
</dependentAssembly>

Solution 4:

In your project's References folder there should be a reference to this dll, and the version should be 2.0.0.0. Make sure this is set to Copy Local = true. And then make sure it finds its way to your server app's bin folder.

This is one of the libraries that is now managed by nuget. So open Nuget and make sure everything is up to date. And in your projects packages directory the file should be here: \packages\System.Net.Http.2.0.20126.16343\lib\net40

You could also try creating a new MVC4 app and see if the file shows up for that one.