Covariance and Contravariance in .NET 4.0

.NET 4 introduces covariance and contravariance in generic interfaces and delegates. Covariance is the ability to use a more derived type than originally specified and will enable you to pass a IEnumerable<T2> as a IEnumerable<T1> if T2 derives from T1.

This webcast walks through some of the variant generic interfaces, show how you can define your own covariant generic interface and also introduce you to variance in generic delegates.

http://twitter.com/CompositeC1

http://www.composite.net/