Ever tried to work through an example, did every step consiously and yet... an error occurs. For example this one:
Failed to load type for module MyModuleName. Error was: the composition remains unchanged. The changes were rejected because of the following error(s): The composition producesd multiple composition errors, with # root causes. The root causes are provided below. Review the CompositionException.Errors propery for more information.
Then follows a list of errors, and none of them points out clearly what went wrong. And the solution is very simple, but crucial to sort out right.
It is this: in the module you want to have composed, you have set references to "Microsoft.Practices.Prism.MefExtensions.dll" and to "Microsoft.Practices.Prism.dll". When you reference these, they are automatically set to "Copy Local=True" in their properties. These two references have to be changed into "Copy Local=False".
Recompile and voila: your application (MEF) composes like you hoped it would!
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