delegate 笔记01

using System;namespace test{    class ABC    {        public int a {get;set;}        public int b {get;set;}        public int ret()        {            return a+b;        }    }    class Program    {        public delegate string GetAString();        public delegate int GetSum(int a, int b);        public delegate int GetABC();        public static int sum(int a, int b)        {            return a + b;        }        static void Main(string[] args)        {            int x = 40;            GetAString firstStringMethod = new GetAString(x.ToString);            Console.WriteLine("String is {0}", firstStringMethod());            //Output: String is 40                        x = 55;            Console.WriteLine("String is {0}", firstStringMethod.Invoke());            //Output: String is 40            ABC abc = new ABC();            abc.a = 3;            abc.b = 4;            GetABC firstABCMethod = new GetABC(abc.ret);            Console.WriteLine("Sum is {0}", firstABCMethod());            //Output: Sum is 7            abc.a = 5;            abc.b = 6;            Console.WriteLine("Sum is {0}", firstABCMethod());            //Output: Sum is 11            int a = 3;            int b = 4;            GetSum firstSumMethod = new GetSum(sum);            Console.WriteLine("Sum is {0}", firstSumMethod(a, b));            //Output: Sum is 7            Console.WriteLine("Sum is {0}", firstSumMethod.Invoke(a, b));            //Output: Sum is 7            Console.Read();        }    }}