事件和委托的例子

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Text;
 4 
 5 namespace Delegate 
 6 {
 7     // 热水器
 8     public class Heater 
 9     {
10        private int temperature;
11        public string type ="RealFire 001";       // 添加型号作为演示
12        public string area = "China Xian";         // 添加产地作为演示
13        //声明委托
14        public delegate void BoiledEventHandler(Object sender, BoiledEventArgs e);
15        public event BoiledEventHandler Boiled;//声明事件
16 
17        // 定义BoiledEventArgs类，传递给Observer所感兴趣的信息
18        public class BoiledEventArgs : EventArgs 
19        {
20            public readonly int temperature;
21            public BoiledEventArgs(int temperature) 
22            {
23               this.temperature = temperature;
24            }
25        }
26 
27        // 可以供继承自 Heater 的类重写，以便继承类拒绝其他对象对它的监视
28        protected virtual void OnBoiled(BoiledEventArgs e) 
29        {
30            if (Boiled != null) 
31            { // 如果有对象注册
32               Boiled(this, e);  // 调用所有注册对象的方法
33            }
34        }
35        
36        // 烧水。
37        public void BoilWater() 
38        {
39            for (int i = 0; i <= 10; i++) 
40            {
41               temperature = i;
42               if (temperature > 5) 
43               {
44                   //建立BoiledEventArgs 对象。
45                   BoiledEventArgs e = new BoiledEventArgs(temperature);
46                   OnBoiled(e);  // 调用 OnBolied方法
47               }
48            }
49        }
50     }
51 
52     // 警报器
53     public class Alarm 
54     {
55        public void MakeAlert(Object sender, Heater.BoiledEventArgs e) 
56        {
57            Heater heater = (Heater)sender;    //这里是不是很熟悉呢？
58            //访问 sender 中的公共字段
59            Console.WriteLine("Alarm：{0} - {1}: ", heater.area, heater.type);
60            Console.WriteLine("Alarm: 嘀嘀嘀，水已经 {0} 度了：", e.temperature);
61            Console.WriteLine();
62        }
63     }
64 
65     // 显示器
66     public class Display 
67     {
68        public static void ShowMsg(Object sender, Heater.BoiledEventArgs e) 
69        {  //静态方法
70            Heater heater = (Heater)sender;
71            Console.WriteLine("Display：{0} - {1}: ", heater.area, heater.type);
72            Console.WriteLine("Display：水快烧开了，当前温度：{0}度。", e.temperature);
73            Console.WriteLine();
74        }
75     }
76 
77     class Program 
78     {
79        static void Main() 
80        {
81            Heater heater = new Heater();
82            Alarm alarm = new Alarm();
83 
84            heater.Boiled += alarm.MakeAlert;   //注册方法
85            heater.Boiled += (new Alarm()).MakeAlert;     //给匿名对象注册方法
86            heater.Boiled += new Heater.BoiledEventHandler(alarm.MakeAlert);   //也可以这么注册
87            heater.Boiled += Display.ShowMsg;       //注册静态方法
88 
89            heater.BoilWater();   //烧水，会自动调用注册过对象的方法
90            Console.ReadKey();
91        }
92     }
93 }

 1 using System;
 2 //步骤1：创建代理对象 
 3 public delegate void MyHandler1(object sender, MyEventArgs e);
 4 public delegate void MyHandler2(object sender, MyEventArgs e);
 5 //步骤2：创建事件处理程序方法 
 6 class A
 7 {
 8     //public const string m_id = "Class A";
 9     public void OnHandler1(object sender, MyEventArgs e)
10     {
11         Console.WriteLine("I am in OnHandler1 and MyEventArgs is {0}", e.m_id);
12     }
13     public void OnHandler2(object sender, MyEventArgs e)
14     {
15         Console.WriteLine("I am in OnHandler2 and MyEventArgs is {0}", e.m_id);
16     }
17     //步骤3：创建代理，安装事件处理程序，并向启动事件的对象注册。 
18     public A(B b)
19     {
20         MyHandler1 d1 = new MyHandler1(OnHandler1);
21         MyHandler2 d2 = new MyHandler2(OnHandler2);
22         b.Event1 += d1;
23         b.Event2 += d2;
24     }
25 }
26 //步骤4：通过代理调用封装的方法。 
27 class B
28 {
29     public event MyHandler1 Event1;
30     public event MyHandler2 Event2;
31     public void FireEvent1(MyEventArgs e)
32     {
33         if (Event1 != null)
34         {
35             Event1(this, e);
36         }
37     }
38     public void FireEvent2(MyEventArgs e)
39     {
40         if (Event2 != null)
41         {
42             Event2(this, e);
43         }
44     }
45 }
46 public class MyEventArgs : EventArgs
47 {
48     public string m_id;
49 }
50 public class Driver
51 {
52     public static void Main()
53     {
54         B b = new B();
55         A a = new A(b);
56         MyEventArgs e1 = new MyEventArgs();
57         MyEventArgs e2 = new MyEventArgs();
58         e1.m_id = "Event args for event 1";
59         e2.m_id = "Event args for event 2";
60         b.FireEvent1(e1);
61         b.FireEvent2(e2);
62         Console.ReadKey();
63     }
64 }