Could not load file or assembly "System.Net.Http, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"

Question

I've copied my project to a clean Windows 10 machine with only Visual Studio 2015 Community and SQL Server 2016 Express installed. There are no other framework versions installed apart from those installed with Windows 10 and VS2015 or SQL Server.

When I try to start the WebApi project I get the message:

Could not load file or assembly "System.Net.Http, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" or one of its dependencies. The system cannot find the file specified.

The project's packages include:

<package id="Microsoft.AspNet.WebApi" version="5.2.3" targetFramework="net45" /> <package id="Microsoft.AspNet.WebApi.Client" version="5.2.3" targetFramework="net45" /> <package id="Microsoft.AspNet.WebApi.Core" version="5.2.3" targetFramework="net45" /> <package id="Microsoft.AspNet.WebApi.Tracing" version="5.2.3" targetFramework="net45" /> <package id="Microsoft.AspNet.WebApi.WebHost" version="5.2.3" targetFramework="net45" /> 

After building the project with .NET Framework 4.6.1, System.Net.Http the file is not found in the bin folder.

The file's path points to:

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.6.1\System.Net.Http.dll

The file's path of System.Net.Http.Formatting points to:

C:\Development\MyApp\packages\Microsoft.AspNet.WebApi.Client.5.2.3\lib\net45\System.Net.Http.Formatting.dll

Should the whole project target 4.5.1 or is there another way to reference the right assemblies?

Answer 1

Changing the binding information in my web.config (or app.config) - while a "hack" in my view, allows you to move forward with your project after a NuGet package update whacks your application and gives you the System.Net.Http error.

Set oldVersion="0.0.0.0-4.1.1.0" and newVersion="4.0.0.0" as follows

<dependentAssembly>     <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />     <bindingRedirect oldVersion="0.0.0.0-4.1.1.0" newVersion="4.0.0.0" /> </dependentAssembly> 

Answer 2

Follow the following steps,

1. Update visual studio to latest version (it matters)
2. Remove all binding redirects from web.config

3. Add this to the .csproj file:

   <PropertyGroup>   <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>   <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType> </PropertyGroup> 

4. Build the project
5. In the bin folder there should be a (WebAppName).dll.config file
6. It should have redirects in it, copy these to the web.config
7. Remove the above snipped from the .csproj file

It should work