Logic and its application to Collections.Generic and inheritance

Question

Everything inherits from object. It\'s the basis of inheritance. Everything can be implicitly cast up the inheritance tree, ie.

object me = new Person();
         


        

Answer 1

While what your trying to does indeed flow logically, its actually a feature that many languages don't natively support. This is whats called co/contra variance, which has to do with when and how objects can be implicitly cast from one thing to nother by a compiler. Thankfully, C# 4.0 will bring covariance and contravariance to the C# arena, and such implicit casts like this should be possible.

For a detailed explanation of this, the following Channel9 video should be helpful:

http://channel9.msdn.com/shows/Going+Deep/Inside-C-40-dynamic-type-optional-parameters-more-COM-friendly/