Microsoft Azure dll throws an exception in .NET 4.0 - json

Question

I have developed on EXE project(use for startup task) and use following dlls of Microsoft Azure ,
It's work very well in .Net framework 3.5 but in my case i need to use system.runtime.serialization to serialize class as json string as per following way
public static string Serialize<T>(T obj)
{
System.Runtime.Serialization.Json.DataContractJsonSerializer serializer = new
System.Runtime.Serialization.Json.DataContractJsonSerializer(obj.GetType());
MemoryStream ms = new MemoryStream();
serializer.WriteObject(ms, obj);
string retVal = Encoding.Default.GetString(ms.ToArray());
ms.Dispose();
return retVal;
}
For this i need to change framework to 4.0 but at that time i got exception from Azure dlls
like
The type initializer for 'Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment' threw an exception
I think all Microsoft's dlls are with backward compatibly so what's going wrong in this matter?
I should find another way to serialize to json string?
OR
I should to change Azure's dlls to latest version?
Thanks in Advance.

Answer 1

If you write a console app in .NET4 and want to use the RoleEnvironment then you’ll get an error:
The type initializer for ‘Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment’ threw an exception.
To get around this, just add a “useLegacyV2RuntimeActivationPolicy” to the startup tag generated in the default app.config:
<startup useLegacyV2RuntimeActivationPolicy="true">
This is because Microsoft.WindowsAzure.ServiceRuntime.dll is a mixed mode assembly. The useLegacyV2RuntimeActivationPolicy attribute is required for referencing any mixed mode assembly, not only the Windows Azure ones.

Answer 2

One thing you might want to check is target framework for your .Net project in Visual Studio. By default when you create a project in VS using .Net framework, it uses ".Net Framework 4 Client Profile". Try changing it to ".Net Framework 4" and see if that helps.