Delegates, Anonymous Methods and Lambda Expressions
Like generics, delegates are one of those features that developers use without really understanding. Initially this wasn’t really a problem since delegates were reserved for fairly specific purposes: implementing callbacks and as the building-block for events (amongst a few other edge cases). However, each version of .NET has seen delegates evolve, first with the introduction of anonymous methods in 2.0 and now with lambda expressions in C# 3.0. With each evolution, delegates have become less of an specific pattern and more of a general purpose tool. In fact, most libraries written specifically for .NET 3.5 are likely to make heavy use of lambda expressions. As always, our concern isn’t just about understanding the code that we use, but also about enriching our own toolset. Seven years ago it wouldn’t have been abnormal to see even a complex system make little (or no) us of delegates (except for using the events of built-in controls). Today, however, even the simplest systems heavily relies on them.
