C# in Depth

Inline delegate actions with anonymous methods145no need to “pollute” the rest of your class with an extra method containing a smallpiece of code that is only useful in one place and doesn’t make sense elsewhere.Anonymous methods also provide some far more powerful behavior in the formof closures, but we’ll come to them in section 5.5. For the moment, let’s stick with relativelysimple stuff—as you may have noticed, a common theme in this book is thatyou can go a long way in C# 2 without dealing with the more complex aspects of thelanguage. Not only is this good in terms of learning the new features gradually, butif you only use the more complicated areas when they provide a lot of benefit, yourcode will be easier to understand as well. First we’ll see examples of anonymousmethods that take parameters but don’t return any values; then we’ll explore thesyntax involved in providing return values and a shortcut available when we don’tneed to use the parameters passed to us.5.4.1 Starting simply: acting on a parameterIn chapter 3 we saw the Action delegate type. As a reminder, its signature is verysimple (aside from the fact that it’s generic):public delegate void Action(T obj)In other words, an Action does something with an instance of T. So anAction could reverse the string and print it out, an Action could printout the square root of the number passed to it, and an Action couldfind the average of all the numbers given to it and print that out. By complete coincidence,these examples are all implemented using anonymous methods in listing 5.5.Listing 5.5Anonymous methods used with the Action delegate typeAction printReverse = delegate(string text){char[] chars = text.ToCharArray();Array.Reverse(chars);Console.WriteLine(new string(chars));};BUses anonymousmethod to createActionAction printRoot = delegate(int number){Console.WriteLine(Math.Sqrt(number));};Action printMean = delegate(IList numbers){double total = 0;foreach (double value in numbers){total += value;}Console.WriteLine(total/numbers.Count);};CUses loop inanonymousmethoddouble[] samples = {1.5, 2.5, 3, 4.5};Licensed to Rhona Hadida