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();         }     } }