Net中委托之三委托的高级应用

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1. 使用委托来解决逻辑分离，解除耦合

2.委托的高级应用实例

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace MyDelegateDemo

{

    public delegate void SayHelloHandler(string name);//1.委托的声明

    public class Greeting

    {

        public static void SayHello(string name, PeopleType type)

        {

            if (type == PeopleType.Chinese)

            {

                Console.WriteLine("早上好,{0}", name);

            }

            else if (type == PeopleType.American)

            {

                Console.WriteLine("Good morning,{0}", name);

            }

        }

        /// <summary>

        /// 委托，逻辑分离，解除耦合

        /// </summary>

        /// <param name="name"></param>

        /// <param name="sayHello">委托的实例</param>

        public static void SayHelloDelegate(string name, SayHelloHandler sayHello)

        {

            sayHello(name);//委托的调用

        }

        public static void SayHelloChinese(string name)

        {

            Console.WriteLine("早上好,{0}", name);

        }

        public static void SayHelloAmerican(string name)

        {

            Console.WriteLine("Good morning,{0}", name);

        }

    }

    public enum PeopleType

    {

        Chinese,

        American

    }

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace MyDelegateDemo

{

    class Program

    {

        //采用委托易于扩展，对扩展开放，对修改封闭的原则

        static void Main(string[] args)

        {

            Console.WriteLine("欢迎来到流星小子博客学习");

            Greeting.SayHello("流星小子", PeopleType.Chinese);

            Greeting.SayHello("Meter", PeopleType.American);

            //委托的实例化

            SayHelloHandler sayHelloHandler = new SayHelloHandler(Greeting.SayHelloChinese);

            Greeting.SayHelloDelegate("流星小子", sayHelloHandler);

            SayHelloHandler sayHello = new SayHelloHandler(Greeting.SayHelloAmerican);

            Greeting.SayHelloDelegate("Meter", sayHello);

            //sayHelloHandler -= Greeting.SayHelloChinese;

            //sayHelloHandler += Greeting.SayHelloAmerican;

            //Greeting.SayHelloDelegate("MeterName", sayHelloHandler);

            //sayHelloHandler -= Greeting.SayHelloAmerican;

            Console.Read();

        }

    }

}