I want to separate concerns here. Create and embed all the UI logic for the Custom XML designer, object model, validations etc in to a separate assembly. Then the Package framework should only register the designer information and ask for a UI Service and everything works magically.
This way I don't need to play with the Package framework (Visual Studio Package) assembly, when I need to modify the UI designer.
This question also applies to anything where you have to separate the UI logic from the Skeleton framework that loads it up, like a plugin.
I have several choices a ServiceProvider model, a plugin model or may be other.
Any samples, suggestions for patterns, links are welcome.
Update 1: What I am looking for is a thought such as - "Does Prism (Composite WPF) fit the bill? Has anyone worked on a project/application which does the separation of concerns just like I mentioned above? etc" (I am still looking out for answers)
I've created a VSPackage that loads an editor. The Editor sits in a separate assembly and implements an interface that I defined. The VSPackage works with the interface, so any changes I make to the editor (and its assembly) does not affect the VSPackage as long as I don't change the interface.