CODEWITHSUNDEEP
c#asp.net.netasp.net-mvc-4nuget
Jammer
Jammer

Reputation: 10206

Odd Exception Scenario System.Net.Http MediaTypeHeaderValue cannot be cast to MediaTypeHeaderValue

I've just started getting this odd Exception being thrown and I'm completely unsure how to move forward and solve it.

[A]System.Net.Http.Headers.MediaTypeHeaderValue cannot be cast to [B]System.Net.Http.Headers.MediaTypeHeaderValue.

Type A originates from 'System.Net.Http, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' in the context 'Default' at location 'C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Net.Http\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Net.Http.dll'.

Type B originates from 'System.Net.Http, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' in the context 'Default' at location 'C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Net.Http\v4.0_2.0.0.0__b03f5f7f11d50a3a\System.Net.Http.dll'

The error occurs in my WebAPI on the client side on this line:

var data = responsecontent.ReadAsAsync<List<MyClass>>().Result;

I've checked every single reference to this DLL both in my web site which hosts the API client and in the API solution. They are all referencing the exact same dll:

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\System.Net.Http.dll

I have noticed that the API is using a newer version of the System.Net.Http.Formatting dll but its only minor version increment and it was updated as a dependency to something else so I'm loathed to try and "downgrade" and create another issue in the process.

API System.Net.Http.Formatting is:

\Microsoft.AspNet.WebApi.Client.4.1.0-alpha-121112\lib\net40\System.Net.Http.Formatting.dll

Web Site System.Net.Http.Formatting is:

\Microsoft.AspNet.WebApi.Client.4.0.30506.0\lib\net40\System.Net.Http.Formatting.dll

I do find it concerning that NuGet will download alpha packages as dependencies even with "Stable Only" selected in the drop down menu.

Upvotes: 3

Views: 4766

Answers (1)

Jammer
Jammer

Reputation: 10206

Turns out that something had gone very wrong with some NuGet updates and it had created a rogue binding redirects in my web.config file on the client side.

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

Changing this back to the previous version:

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

Fixed everything on the client side.

Upvotes: 11

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