使用委托来减少if..else判断

来源：互联网发布：x4软件怎么下载编辑：程序博客网时间：2024/05/05 20:43

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace _13{    public class ClassPeople    {        public void SayChinese(string name)        {            Console.WriteLine("你好," + name);        }        public void SayEnglish(string name)        {            Console.WriteLine("Hello," + name);        }        public enum Language        {            English, Chinese        }        public void DoWork(string name, Language lang)        {            switch (lang)            {                case Language.English:                    SayEnglish(name);                    break;                case Language.Chinese:                    SayChinese(name);                    break;            }        }    }    class Program    {        static void Main(string[] args)        {            ClassPeople cp = new ClassPeople();            cp.DoWork("李天平", ClassPeople.Language.Chinese);            cp.DoWork("litianping", ClassPeople.Language.English);            System.Console.ReadLine();        }    }}

上述代码，根据传进来的语言枚举值和名字符串来输出相应语言的问候语，不过，这个方法的可扩展性太差了，如果以后我们需要再添加韩文版，日文版，就不得不反复修改枚举和Dowork()方法，以适应新的需求。

使用委托可以解决优化此类问题。

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace _14{    public delegate void SayDelegate(string name);    public class ClassPeople    {        public void SayChinese(string name)        {            Console.WriteLine("你好," + name);        }        public void SayEnglish(string name)        {            Console.WriteLine("Hello," + name);        }        //注意此方法，它接受一个SayDelegate类型的方法作为参数        public void DoWork(string name, SayDelegate MakeSay)        {            MakeSay(name);        }    }    class Program    {        static void Main(string[] args)        {            ClassPeople cp = new ClassPeople();            cp.DoWork("李天平", cp.SayChinese);            cp.DoWork("litianping", cp.SayEnglish);            System.Console.ReadLine();        }    }}

优化化，我们要加一种问候语，只要新增一个方法就可以了

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