Phew that blog post title sure is a mouthful! (As you can see I wanted to get all the key words into the title!) So what's this post really about? I am making an ASP.NET Forms Application composable using the new Managed Extensibility Framework (MEF). By composable I mean that I have for instance a Page that hosts dynamically loaded UserControls. Page and Controls may all communicate with one another but I want to do it without having to hook them up to each other manually. Also you don't want to set compile time references between any different assemblies...