New Post: Is MEF compatible with the article "WPF Hands-On Lab: Get Started with the Prism Library" ?

Follow the instruction in http://msdn.microsoft.com/en-us/library/ff921141%28v=pandp.40%29.aspx, I create a WPF application.

Every thing was OK as the article said.

The article said: "This hands-on lab uses the Unity container, but you can also use the Managed Extensibility Framework (MEF) with the Prism Library."

Now I want to use MEF instead of Unity. So I

1. added
   reference to Microsoft.Practices.Prism.MefExtensions
2. added
   using Microsoft.Practices.Prism.MefExtensions;
3. modify
   class Bootstrapper:UnityBootstrapper
   to
   class Bootstrapper:MefBootstrapper
   

Then I got the ModuleTypeLoaderNotFoundException with message:
"There is currently no moduleTypeLoader in the ModuleManager that can retrieve the specified module."

How to fix it ?