I stumbled across a collection type the other day that was implemented with .NET 2.0. This, like many other things in 2.0 slipped past me completely until now. This collection type offers a solution to a common problem; How do you expose the collections in your class but prevent the consumer from modifying them? This is a "problem" with all reference types really, but often it is desirable to expose your collections to consumers. To illustrate this problem consider the following class:   public class [...]