C# 委托 事件

一：什么叫委托

通过反射发现，委托其实是一个类，继承自System.MulticastDelegate，但是System.MulticastDelegate这个类是特殊类，不能被继承

 

二：委托的声明 

 public delegate void NoReturnNoParaOutClass();
 public class MyDelete
 {
      public delegate void NoReturnNoPara<T>(T t);
      public delegate void NoReturnNoPara();
      public delegate void NoReturnWithPara(int x, int y);
      public delegate int WithReturnNoPara();
      public delegate string WithReturnWithPara(out int x, ref int y);
    }

委托可以声明在类外面，可以声明再类里面

 

三：委托的实例和调用 

      private int GetSomething()
        {
            return 1;
        }
        private int GetSomething2()
        {
            return 2;
        }

        private int GetSomething3()
        {
            return 3;
        }
        private void DoNothing()
        {
            Console.WriteLine("This is DoNothing");
        }
        private static void DoNothingStatic()
        {
            Console.WriteLine("This is DoNothingStatic");
        }
        public string ParaReturn(out int x, ref int y)
        {
            throw new Exception();
        }

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