c#委托与事件2

首先是一个关机器的一般方法：

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

 namespace DelegateDemo
 {
     class Program
     {
         static void Main(string[] args)
         {
             FoldingMachine folder = new FoldingMachine();
             WeldingMachine welder = new WeldingMachine();
             PaintingMachine painter = new PaintingMachine();

             Controller controller = new Controller();
             controller.Folder = folder;
             controller.Welder = welder;
             controller.Painter = painter;
             controller.ShutDown();
             Console.ReadKey();
         }
     }
 }

Program.cs

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

 namespace DelegateDemo
 {
     class Controller
     {
         private FoldingMachine folder;
         private WeldingMachine welder;
         private PaintingMachine painter;
         public void ShutDown()
         {
             folder.FinishFolding();
             welder.FinishWelding();
             painter.PaintOff();
         }
         public FoldingMachine Folder
         {
             set { this.folder = value; }
         }

         public WeldingMachine Welder
         {
             set { this.welder = value; }
         }

         public PaintingMachine Painter
         {
             set { this.painter = value; }
         }

     }
 }

Controller.cs

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

 namespace DelegateDemo
 {
     class FoldingMachine
     {
         public void StopFolding(int ShutDownTime)
         {
             Console.WriteLine("stop FoldingMachine");
         }

         public void FinishFolding()
         {
             StopFolding();
         }
     }
 }

FoldingMachine.cs

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

 namespace DelegateDemo
 {
     class PaintingMachine
     {
         public void PaintOff()
         {
             Console.WriteLine("stop PaintingMachine");
         }
     }
 }

PaintingMachine.cs

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

 namespace DelegateDemo
 {
     class WeldingMachine
     {
         public void FinishWelding()
         {
             Console.WriteLine("stop WeldingMachine.");
         }
     }
 }

WeldingMachine.cs

---

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

 namespace DelegateDemo
 {
     class Program
     {
         static void Main(string[] args)
         {
             FoldingMachine folder = new FoldingMachine();
             WeldingMachine welder = new WeldingMachine();
             PaintingMachine painter = new PaintingMachine();

             Controller controller = new Controller();
             controller.Folder = folder;
             controller.Welder = welder;
             controller.Painter = painter;
             controller.ShutDown();
             controller.StopManchinery();
             Console.ReadKey();
         }
     }
 }

Program.cs

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

 namespace DelegateDemo
 {
     class Controller
     {
         private FoldingMachine folder;
         private WeldingMachine welder;
         private PaintingMachine painter;
         public delegate void  stopManchineryDelegate();
         stopManchineryDelegate stopManchinery;

         public Controller()

         {

             //
         }
         public stopManchineryDelegate StopManchinery
         {
             get { return stopManchinery; }
             set { stopManchinery += value; }
         }
          public void SetStopManchinery()
         {
             //stopManchinery = new stopManchineryDelegate(folder.StopFolding);
             stopManchinery += folder.StopFolding;
             stopManchinery += welder.FinishWelding;
             stopManchinery += painter.PaintOff;

         }
         public void ShutDown()
         {
             //folder.FinishFolding();
             //welder.FinishWelding();
             //painter.PaintOff();
             SetStopManchinery();
         }
         public FoldingMachine Folder
         {
             set { this.folder = value; }
         }

         public WeldingMachine Welder
         {
             set { this.welder = value; }
         }

         public PaintingMachine Painter
         {
             set { this.painter = value; }
         }

     }
 }

Controller.cs

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

 namespace DelegateDemo
 {
     class FoldingMachine
     {
         public void StopFolding()
         {
             Console.WriteLine("stop FoldingMachine");
         }

         public void FinishFolding()
         {
             StopFolding();
         }
     }
 }

FoldingMachine

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

 namespace DelegateDemo
 {
     class PaintingMachine
     {
         public void PaintOff()
         {
             Console.WriteLine("stop PaintingMachine");
         }
     }
 }

PaintingMachine

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

 namespace DelegateDemo
 {
     class WeldingMachine
     {
         public void FinishWelding()
         {
             Console.WriteLine("stop WeldingMachine.");
         }
     }
 }

WeldingMachine.cs

注意委托（其实就是指针，指向函数的指针，也就是函数指针）的参数要与所指向的函数的参数相同，体现到代码中就是FoldingMachine.cs中的修改。另外一个类中的字段即使是public也不能在另一个类中直接使用，所以代码中使用了方法（controller.StopManchinery();）来使用另一个类中的委托。

---

lamada表达式：

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事件：

事件的调用只能在定义事件的类的内部调用，无论是用public还是private修饰事件。委托违反了封装的原则，事件封装委托，保证了封装。

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参考：http://blog.csdn.net/jamestaosh/article/details/4372172

要创建一个事件驱动的程序需要下面的步骤：

1.         声明关于事件的委托；

2.         声明事件；

3.         编写触发事件的函数；

4.         创建事件处理程序；

5.         注册事件处理程序；

6.         在适当的条件下触发事件。 

现在我们来编写一个自定义事件的程序。主人养了一条忠实的看门狗，晚上主人睡觉的时候，狗负责看守房子。一旦有小偷进来，狗就发出一个Alarm事件，主人接到Alarm事件后就会采取相应的行动。假设小偷于2009年元旦午夜时分到达。

//事件发送者

class Dog
{
    //1.声明关于事件的委托；
    public delegate void AlarmEventHandler(object sender, EventArgs e);

    //2.声明事件；
    public event AlarmEventHandler Alarm;

    //3.编写引发事件的函数；
    public void OnAlarm()
    {
        if (this.Alarm != null)
        {
            Console.WriteLine("/n狗报警: 有小偷进来了,汪汪~~~~~~~");
            this.Alarm(this, new EventArgs());   //发出警报
         }
    }
}

//事件接收者
class Host
{
    //４.编写事件处理程序
    void HostHandleAlarm(object sender, EventArgs e)
    {
        Console.WriteLine("主  人: 抓住了小偷！");
    }

    //５.注册事件处理程序
    public Host(Dog dog)
    {
        dog.Alarm += new Dog.AlarmEventHandler(HostHandleAlarm);
    }
}

//６.现在来触发事件
class Program
{
    static void Main(string[] args)
    {
        Dog dog = new Dog();
        Host host = new Host(dog);

        //当前时间，从2008年12月31日23:59:50开始计时
        DateTime now = new DateTime(2008, 12, 31, 23, 59, 50);
        DateTime midnight = new DateTime(2009, 1, 1, 0, 0, 0);

        //等待午夜的到来
        Console.WriteLine("时间一秒一秒地流逝... ");
        while (now < midnight)
        {
            Console.WriteLine("当前时间: " + now);
            System.Threading.Thread.Sleep(1000);   //程序暂停一秒
            now = now.AddSeconds(1);                //时间增加一秒
         }

        //午夜零点小偷到达,看门狗引发Alarm事件
        Console.WriteLine("/n月黑风高的午夜: " + now);
        Console.WriteLine("小偷悄悄地摸进了主人的屋内... ");
        dog.OnAlarm();
    }
} 

---

http://blog.csdn.net/Wiiix/article/details/51463977

下面再看一个例子:

在我们创建一个事件之前，我们需要一个委托，而一般标准的委托声明如下:

public delegate void EventHandler(object sender, System.EventArgs e);

第一个形参object sender定义了对象来源，第二个形参放的是继承自System.EventArgs的类，一般上这个类包含了事件的详细信息。

例子:

class ButtonEventArgs:EventArgs

{

public string time;

}

在这里我们不需要传递什么事件信息，所以我们用基类EventArgs就好。

  public delegate void EventHandler(object sender, System.EventArgs e);

     class Publisher
     {
         public event EventHandler Added; //定义发生事件

         protected virtual void OnAdded(System.EventArgs e) //当事件发生中触发方法
         {
             if(Added!=null)
             {
                 Added(this, e);
             }
         }
         public void Add(object value) //触发事件的方法
         {

             OnAdded(System.EventArgs.Empty);
         }
 }

     class Subscriber
     {
         void AddedEventHandler(object sender,System.EventArgs e)
         {
             System.Console.WriteLine("AddEvent occured");
         }

         static void Main()
         {
             Subscriber s = new Subscriber();
             Publisher p = new Publisher();
             p.Added += s.AddedEventHandler;
 p.Add();
         }
 }

事件的使用步骤如下:

存放事件的类

1.定义事件

2.触发事件的方法(protected)

3.间接触发事件的方法(public)

触发事件的类

1.定义方法

2.注册方法

3.触发方法

---

http://www.cnblogs.com/yinqixin/p/5067033.html

---

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

 namespace 自定义事件一
 {
     class Program
     {
         static void Main(string[] args)
         {
             Dog dog = new Dog();
             Host host = new Host(dog );
             DateTime now = new DateTime(, , , , , );
             DateTime midnight = new DateTime(, , , , , );
             while (now < midnight)
             {
                 Console.WriteLine("当前时间" + now);
                 System.Threading.Thread.Sleep();
                 now = now.AddSeconds();
             }
             Console.WriteLine("\n月黑风高的午夜：" + now);
             Console.WriteLine("小偷进了主人的屋内...........");
             dog.OnAlarm();
             Console.ReadKey();
         }
     }
     class Dog
     {
         //第一：声明关于事件的委托
         public delegate void AlarmEventHandler(object sender, EventArgs e);
         //第二：声明事件
         public event AlarmEventHandler Alarm;//前面的public没用，这个Alarm事件仍然是private的，可以在类外绑定方法，不能运行这个事件
         //第三：编写引发shijian的函数
         public void OnAlarm()
         {
             if (this.Alarm != null)
             {
                 Console.WriteLine("\n狗报警，有小偷进来了，汪汪汪~~~");
                 this.Alarm(this, new EventArgs());//运行这个事件；this 当前对象，this.Alarm是当前对象多引用的事件
             }
         }
     }
     class Host
     {
         //第四：编写事件的处理程序
         void HostHandeAlarm(object sender, EventArgs e)
         {
             Console.WriteLine("主人：抓住了小偷！~");
         }
         //第五：注册事件的处理程序
         public Host(Dog dog)
         {
             dog.Alarm  += new Dog.AlarmEventHandler(HostHandeAlarm);
         }
     }

 }