委托

委托：可以理解为装载方法的容器，可以转载方法的指针

namespace 委托
{
    class Program
    {
        static void Main(string[] args)
        {
            //第一版：原始委托
            Main1 m = new Main1();
            m.Run();

            //第二版：委托参数版
            m.RunHandler(x=> { Console.WriteLine(x + "+rum"); },"王五");


            //第三版：Action实现委托
            m.Handle(x => { Console.WriteLine(x + "无返回值"); },"赵六");

            //第三版：Func实现委托
            string res = m.Handle(x => x + "func有返回值", "田七");
            Console.WriteLine(res);
            Console.ReadKey();
        }
    }
}


namespace 委托
{
    public class Main1
    {
        public delegate void HandlerEven(string name);

        /*
         * 委托转载方法的容器，定义好方法的入参和返回值
         * 第一版：原始委托
         */
        public void Run()
        {
            HandlerEven say1 = Say;
            HandlerEven say2 = new HandlerEven(Say);
            say2 += Say2;
            say1("张三");
            say2("李四");
        }
        public void Say(string name)
        {
            Console.WriteLine("run+" + name);
        }

        public void Say2(string name)
        {
            Console.WriteLine("run2+" + name);
        }



        /*
         * 第二版：委托参数版
         */
        public void RunHandler(HandlerEven say,string name)
        {
            say(name);
        }


        /*
         * 第三版：微软内置委托Action:无返回值 Func:有一个返回值
         */
        public void Handle(Action<string> action,string name)
        {
            action(name);
        }

        public string Handle(Func<string,string>fun ,string name)
        {
            return fun(name);
        }

    }
}

委托实现观察者模式：

   
     public class Delegates
    {
        public delegate void HandlerEven(string name);
        public void Run()
        {
            HandlerEven say = CatSay;
            say += MouseRun;
            say += Sleep;
            say("叫");
        }
        public void CatSay(string name)
        {
            Console.WriteLine("猫叫了：" + name);
        }

        public void MouseRun(string name)
        {
            Console.WriteLine("吓跑了老鼠：" + name);
        }

        public void Sleep(string name)
        {
            Console.WriteLine("惊醒了主人：" + name);
        }


        public void SecondRun()
        {
            List<Action<string>> list = new List<Action<string>>();
            list.Add(CatSay);
            list.Add(MouseRun);
            list.Add(Sleep);
            foreach (var item in list)
            {
                item("second");
            }
        }
        public void Handle(Action<string> action, string name)
        {
            action(name);
        }
    }

主代码调用：

    class Program
    {

        static void Main(string[] args)
        {
            Delegates de = new Delegates();
            de.Run();
            de.SecondRun();
            Console.ReadKey();
        }  
    }