C# 5 in a Nutshell - Delegate

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1. What is delegate in C#?

A delegate is an object that knows how to call a method.
A delegate type defines the kind of method that delegate instances can call. Specifically,
it defines the method’s return type and its parameter types.

The followingdefines a delegate type called Transformer:
delegate int Transformer (int x);

 Transformer is compatible with any method with an int return type and a single
int parameter, such as this:
static int Square (int x) { return x * x; }
Assigning a method to a delegate variable creates a delegate instance:
Transformer t = Square;

 

complete code:

public delegate int Transformer (int x);class Util{    public static void Transform (int[] values, Transformer t)    {        for (int i = 0; i < values.Length; i++)        values[i] = t (values[i]);    }}class Test{    static void Main()    {        int[] values = { 1, 2, 3 };        Util.Transform (values, Square); // Hook in the Square method        foreach (int i in values)        Console.Write (i + " "); // 1 4 9    }    static int Square (int x) { return x * x; }}

 

C# 5 in a Nutshell - Delegate