委托的实现过程

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 面试题案例
{
    class 委托
    {
         public  void   初级版()
        {
            int inputSelected = 1;
            while (inputSelected == 1)
            {
                Console.WriteLine("请输入名字");

                string inputName = Console.ReadLine();
                GreetPeople(inputName);
                Console.WriteLine("请选择 1：继续，2：退出");
                inputSelected = int.Parse(Console.ReadLine());
            } 
        }
        public void  过渡版()
        {          
            int inputSelected = 1;
            while (inputSelected == 1)
            {
                Console.WriteLine("请选择国家 1：美国人 2中国人");

                string inputCountry = Console.ReadLine();
                Console.WriteLine("请输入名字");
                string inputName = Console.ReadLine();
                if (inputCountry == "1")
                {
                    GreetPeople(inputName, Language.Enlish);
                }
                else
                {
                    GreetPeople(inputName, Language.Chinese);
                }

                Console.WriteLine("请选择 1：继续，2：退出");
                inputSelected = int.Parse(Console.ReadLine());
            }
        }

        public void 终极版()
        {
            int inputSelected = 1;
            while (inputSelected == 1)
            {
                Console.WriteLine("请选择国家 1：美国人 2中国人");
                string inputCountry = Console.ReadLine();
                Console.WriteLine("请输入名字");
                string inputName = Console.ReadLine();
                if (inputCountry == "1")
                {
                    GreetPeople(inputName,EnlishGreeting);
                }
                else
                {
                    GreetPeople(inputName, ChineseGreeting);
                }
                Console.WriteLine("请选择 1：继续，2：退出");
                inputSelected = int.Parse(Console.ReadLine());

            }
        }
        #region 什么是委托
        public void GreetPeople(string name)
        {
            EnlishGreeting(name); 
          
        }
        public void GreetPeople(string name, Language lang)
        {
            switch (lang)
            {
                case Language.Enlish:
                    EnlishGreeting(name);
                    break;
                case Language.Chinese:
                    ChineseGreeting(name);
                    break;
            }
        }
        public void EnlishGreeting(string name)
        {

            Console.WriteLine("GoodMorining  " + name);
            Console.ReadKey();
        }
        public void ChineseGreeting(string name)
        {
            Console.WriteLine("早上好  " + name);
            Console.ReadKey();
        }
        #endregion

        public enum Language
        {
            Enlish, Chinese
        }
        
        public delegate void GreetingDelegate(string name);        

        public void GreetPeople(string name,GreetingDelegate MakeGreeting)
        {
            MakeGreeting(name);
        }
       
    }
}

使用

 委托 weituo = new 委托();
            Console.WriteLine("请选择使用的版本 1: 初级版，2：过渡板  3：终极版" );
            string input_selected = Console.ReadLine();
            int flag = 1;
            while (flag==1)
            {
                if (input_selected=="1")
                {
                    weituo.初级版(); 
                }
                else if (input_selected=="2")
                {
                    weituo.过渡版();

                }
                else if (input_selected == "3")
                {
                    weituo.终极版();

                }
                Console.WriteLine("1 ：继续 2：退出");
                flag = int.Parse( Console.ReadLine());

            }