C#: Method to return object whose concrete type is determined at runtime?

Question

I\'m thinking about designing a method that would return an object that implements an interface but whose concrete type won\'t be know until run-time. For example suppose:

Answer 1

You would want just a virtual method, SpecificationMethod, which is implemented in each class. I recommend reading FAQ Lite's content on inheritence. The design method's he mentions can be applied to .Net as well.