C# in Depth

160 CHAPTER 5 Fast-tracked delegates5.6 SummaryC# 2 has radically changed the ways in which delegates can be created, and in doingso it’s opened up the framework to a more functional style of programming. Thereare more methods in .NET 2.0 that take delegates as parameters than there were in.NET 1.0/1.1, and this trend continues in .NET 3.5. The List type is the bestexample of this, and is a good test-bed for checking your skills at using anonymousmethods and captured variables. Programming in this way requires a slightly differentmind-set—you must be able to take a step back and consider what the ultimateaim is, and whether it’s best expressed in the traditional C# manner, or whether afunctional approach makes things clearer.All the changes to delegate handling are useful, but they do add complexity to thelanguage, particularly when it comes to captured variables. Closures are always trickyin terms of quite how the available environment is shared, and C# is no different inthis respect. The reason they’ve lasted so long as an idea, however, is that they canmake code simpler to understand and more immediate. The balancing act betweencomplexity and simplicity is always a difficult one, and it’s worth not being too ambitiousto start with. As anonymous methods and captured variables become more common,we should all expect to get better at working with them and understanding whatthey’ll do. They’re certainly not going away, and indeed LINQ encourages their useeven further.Anonymous methods aren’t the only change in C# 2 that involves the compiler creatingextra types behind the scenes, doing devious things with variables that appear tobe local. We’ll see a lot more of this in our next chapter, where the compiler effectivelybuilds a whole state machine for us in order to make it easier for the developerto implement iterators.Licensed to Rhona Hadida