一个简单的委托

 class Delegate123
    {
        public delegate void HelloHander(string msg);
        private void Hello1(string msg)
        {
            Console.WriteLine("Hello1"+msg);
        }
        private void Hello2(string msg)
        {
            Console.WriteLine("Hello2" + msg);
        }
        private void Hello3(string msg)
        {
            Console.WriteLine("Hello3" + msg);
        }
        static void Main(string[] args)
        {
            Delegate123 delegate123 = new Delegate123();
            HelloHander hello = new HelloHander(delegate123.Hello1);
            hello += new HelloHander(delegate123.Hello2);
            hello += new HelloHander(delegate123.Hello3);
            hello -= new HelloHander(delegate123.Hello2);
            if (hello != null)
                hello("你好");
            Console.ReadLine();
        }
    }

这个讲的不错：http://blog.csdn.net/Knight94/archive/2006/11/15/1385284.aspx