How can I figure out what didn't load in MEF

I had a class and I typed in the concrete class rather then the interface that was registered.

Is there a way to debug this sort of thing in visual studio?

I don't really want to use mefx because it se开发者_JAVA技巧emed to crash on me when I tried it.

I think Daniel Plaisted's post on that topic covered it pretty well. If you don't like mefx, you can examine the rejection trace in the debugger's output window, or you can use the composition diagnostics assembly to print the composition information yourself.