事件 和 委托

收集的代码 事件和委托
委托会在后面赋值的时候被覆盖，事件赋值一个执行一个，一下收集的测试代码

----------------系统委托EventHandler

----------------------------事件(封装)
    public event SearchHandler search;
    public event SearchHandler Search {
        add {
            search += value;
        }
        remove {
            search -= value;
        }
    }

--------------------------------------------------------------------简单的委托例子

 

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

 namespace T2
 {
     //委托必须是参数类型和返回类型相同，并且用deletegate修饰
    class Computer
     {
         public int Add(int x, int z) {
             return x + z;
         }

         public int Sub(int x, int z)
         {
             return x - z;
         }
         //属性委托
        public delegate int ComputerHander(int x, int z);
         public ComputerHander ch=null;
     }
     //类委托
    public delegate int ComputerHander(int x, int z);
 }

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

 namespace T2
 {
     class Program
     {
         static void Main(string[] args)
         {
             //Computer的例子
            Computer c = new Computer();
             //调用类委托
            ComputerHander hander = c.Add;
             Console.WriteLine(hander(1,2));
             //调用属性委托
            c.ch = c.Sub;
             Console.WriteLine(c.ch(1, 2));

         }
     }
 }

 

--------------------------------------------------------------用方法做参数的委托

 

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

 namespace T2
 {
     //定义一个业务逻辑类
    class HelloManager
     {
         //把委托作为方法的参数
        public void SayHello(string name, HelloHander hander) {
             hander(name);
         }
     }

     //定义中国人类
    class Chinaes
     {
         public static void ChinesHello(string name) {
             Console.WriteLine("ChinesHello," + name);
         }
     }

     //定义英国人类
    class English
     {
         public static void EnglishHello(string name)
         {
             Console.WriteLine("EnglishHello," + name);
         }
     }

     //定义委托
    public delegate void HelloHander(string name);
 }


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

 namespace T2
 {
     class Program
     {
         static void Main(string[] args)
         {
             //调用HelloManager的例子
            HelloManager h = new HelloManager();
             h.SayHello("哈哈",English.EnglishHello);
         }
     }
 }

------------------------------------------------------------------自定义事件

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

 namespace T2
 {   //自定义注册事件
    //猫是事件原，所以事件类型要在猫类里面定义
    class Cat
     {
         //定义委托
        public delegate void CryHander();
         //定义事件，委托类型
        public event CryHander CryEvent;
         public void Cry() {
             Console.WriteLine("猫大叫一声...");
             if (CryEvent != null) {
                 CryEvent();//执行事件
            }
         }
     }

     //老鼠
    class Mouse {
         public void Run() {
             Console.WriteLine("老鼠逃跑了....");
         }
     }

     //主人
    class Master {
         public void Weak() {
             Console.WriteLine("主人醒了....");
         }
     }
 }
using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;

 namespace T2
 {
     class Program
     {
         static void Main(string[] args)
         {
             //动态注册事件
            Cat cat = new Cat();
             Mouse mouse = new Mouse();
             Master master = new Master();

             //订阅事件，多播性
            cat.CryEvent += new Cat.CryHander(mouse.Run);
             cat.CryEvent += new Cat.CryHander(master.Weak);

             //触发事件
            cat.Cry();
         }
     }
 }

--------------------------------------带参数的事件

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

 namespace T2
 {
     //事件类型
    public class QuestionEvenArgs : EventArgs
     {
         public string QuestionMes{get; set; }
     }
     //委托
    public delegate void QuestionHander(object sendr,QuestionEvenArgs e);
     //主持人类
    public class Host
     {
         public event QuestionHander AnswerQuestion;
         public string Name { get; set; }
         public string Question { get; set; }//问题
        //触发事件方法
        public void Start()
         {
             Console.WriteLine("大家好，我是:" + Name);
             Console.WriteLine("今天的问题是:" + Question);
             Console.WriteLine("请各位嘉宾开始回答");
             //通知所有嘉宾回答问题
            if (AnswerQuestion != null)
             {
                 AnswerQuestion(this, new QuestionEvenArgs { QuestionMes = Question });
             }
         }
     }
     //嘉宾抽象类--父类
    public abstract class Guest {
         public string Name { get; set; }

         public abstract void Answer(object sendr, QuestionEvenArgs e);
     }
     public class GuestA : Guest
     {
         public override void Answer(object sendr, QuestionEvenArgs e)
         {
            
             Console.WriteLine(Name + ",这个问题是我考虑一下！");
         }
     }
     public class GuestB : Guest
     {
         public override void Answer(object sendr, QuestionEvenArgs e)
         {

             Console.WriteLine(Name + ",这个问题我知道！");
         }
     }
     public class GuestC : Guest {
         public override void Answer(object sendr, QuestionEvenArgs e)
         {
             Host h = sendr as Host;
             Console.WriteLine(h.Name+",这个问题是"+e.QuestionMes+",我知道答案，但是我不告诉你");
         }
     }

     public class Test {
         public static void Main(string[] args) {
             Host h = new Host { Name = "李咏", Question = "伦敦奥运什么时候开始？" };

             GuestA a = new GuestA { Name = "AAA" };
             GuestB b = new GuestB { Name = "BBB" };
             GuestC c = new GuestC { Name = "CCC" };

             h.AnswerQuestion += new QuestionHander(a.Answer);
             h.AnswerQuestion += new QuestionHander(b.Answer);
             h.AnswerQuestion += new QuestionHander(c.Answer);

             h.Start();
         }
     }
 }