Can't update to Web API 2.1

Question

I'm trying to update my Web API from 2.0 to 2.1 but I have the following error

Could not load file or assembly 'System.Web.Http, Version=5.0.0.0, 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)

at this line

GlobalConfiguration.Configure(WebApiConfig.Register);

in the global.asax.cs when I run the API after the update.

but it's normal because it's referencing 5.1.0 in the csprog

<Reference Include="System.Web.Http, Version=5.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">

I tried also with the command line

Install-Package Microsoft.AspNet.WebApi -Version 5.1.0

and I have the same problem but sometimes it gives me an error saying that some plugins depend on Microsoft.AspNet.WebApi.core 5.0.0.

but I don't understand why because the plugin's dependencies are Microsoft.AspNet.WebApi.core >= 5.0.0. so 5.1.0 should work.

I tried to update and ignore dependencies with

Install-Package -Ignoredependencies Microsoft.AspNet.WebApi -Version 5.1.0

and I don't have the error anymore but the API returns error 500.

Any idea why the update to Web API 2.1 doesn't work?

Answer 1

Do you have assembly binding redirect?

<runtime>
      <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
           <dependentAssembly>
               <assemblyIdentity name="System.Web.Http" publicKeyToken="31bf3856ad364e35" culture="neutral" />
               <bindingRedirect oldVersion="0.0.0.0-5.1.0.0" newVersion="5.1.0.0" />
           </dependentAssembly>
    </assemblyBinding>
</runtime>