Exception: "The assembly used when compiling might be different than that used when loading and the type is missing."

Topics: Prism v2 - WPF 3.5
Feb 17, 2010 at 4:44 PM

I am building a Prism app with several modules, one of which (MyModule) contains a user control (MyUserControl) that I created. MyUserControl tests fine, but when I add it to MyModule and run the app, I get this exception:

"Cannot find type 'MyUserControl'. The assembly used when compiling might be different than that used when loading and the type is missing."

I can fix the error by adding a reference to MyUserControl to my Shell application. But of course, that defeats the whole purpose of Prism, since the Shell does not use MyUserControl--only MyModule uses it.

MyUserControl is based on the WPF Calendar control from the WPF Toolkit, which seems to have a similar problem.

Any suggestions on how to fix this problem without coupling the Shell to MyUserControl? Thanks.