I realize this thread is old but I'm trying to do the same thing. I have a WPF/Prism EXE that I converted to a DLL that I need to start from a Class Library. I created an entry point that calls the bootstrapper and the shell window appears but fails when
I try to inject a view into a region as the RegionManager doesn't recognize the region names. (The EXE I started with works as expected so it's setup as a valid Prism application). I did verify that ConfigureAggregateCatalog is being called and my MEF exports
are being picked up so it's not an issue there.
I tried the same thing with the Hello World Quickstart and the shell opens but the module isn't loaded into the region.
Here is my code from InitializeShell in the bootstrapper:
Window mainWindow = (Window)CreateShell();
mainWindow.Dispatcher.Invoke(DispatcherPriority.Normal, new Action(delegate()