c# – Allow mixed mode for assemblys in Visual Studio

c# – Allow mixed mode for assemblys in Visual Studio

If you have the requirement to use a *.dll that was compiled in an older .Net Version (for example .Net 2.0) and you are using them in a .Net 4.0 Project then it is possible that you get the following error message:

Mixed mode assembly is built against version ‘v2.0.50727′ of the runtime   and cannot be loaded in the 4.0 runtime without additional  configuration Information..

To fix this issue you have to do the following:

Applications/Services: (App.config File)

<configuration>
<startup useLegacyV2RuntimeActivationPolicy="true">
</startup>
</configuration>

WCFSVCHost Debugger: (Path: C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\WcfSvcHost.exe.config File)

<configuration>
<startup useLegacyV2RuntimeActivationPolicy="true">
</startup>
</configuration>