1:
2: using System;
3: using System.Collections.Generic;
4: using System.Linq;
5: using System.Text;
6:
7: namespace CSharp.Event
8: {
9: public delegate void MyEventHandler(string s);
10:
11: public interface IPublisher
12: {
13: // 接口可声明事件。
14: event EventHandler RaiseCustomEvent;
15: //自定义事件访问器，可选
16: event MyEventHandler OnMyEvent;
17: }
18:
19: ///
20: /// 自定义EventArgs类，用来保存事件信息
21: ///
22: public class CustomEventArgs : EventArgs
23: {
24: private string message;
25:
26: public string Message
27: {
28: get { return message; }
29: set { message = value; }
30: }
31:
32: public CustomEventArgs(string s)
33: {
34: message = s;
35: }
36:
37: }
38:
39: ///
40: /// 发布者
41: ///
42: class Publisher : IPublisher
43: {
44: object objectLock = new Object();
45: //使用EventHandler 声明事件
46: public event EventHandler RaiseCustomEvent;
47: private event MyEventHandler _myEventHandler;
48:
49: ///
50: /// 在大多数情况下都不需要提供自定义的事件访问器。
51: /// 如果您在代码中没有提供自定义的事件访问器，编译器会自动添加事件访问器。
52: ///
53: public event MyEventHandler OnMyEvent
54: {
55: add
56: {
57: lock (objectLock)
58: {
59: _myEventHandler += value;
60: }
61: }
62: remove
63: {
64: lock (objectLock)
65: {
66: _myEventHandler -= value;
67: }
68: }
69: }
70:
71: public void DoSomething()
72: {
73: //省略。。。
74:
75: //自己引发事件
76: OnRaiseCustomEvent(new CustomEventArgs("Did something"));
77: //省略。。。
78:
79: if (_myEventHandler != null)
80: {
81:
82: _myEventHandler("你轻轻的走，不带走一片云彩！");
83: }
84:
85: }
86:
87: ///
88: /// 公开protected virtual方法，允许继承类重写事件调用行为
89: ///
90: ///
91: protected virtual void OnRaiseCustomEvent(CustomEventArgs e)
92: {
93: EventHandler handler = RaiseCustomEvent;
94:
95: //如果没有订阅者，事件为空
96: if (handler != null)
97: {
98: e.Message += String.Format(" at {0}", DateTime.Now.ToString());
99:
100: //触发事件
101: handler(this, e);
102: }
103: }
104:
105:
106: }
107:
108: ///
109: /// 订阅者
110: ///
111: class Subscriber
112: {
113: private string id;
114: public Subscriber(string ID, Publisher pub)
115: {
116: id = ID;
117: //多路广播委托实现事件订阅
118: pub.RaiseCustomEvent += HandleCustomEvent;
119: pub.OnMyEvent += new MyEventHandler(pub_OnMyEvent);
120: }
121:
122: void pub_OnMyEvent(string s)
123: {
124: Console.WriteLine(string.Format("{0} 的开场白：{1}", id, s));
125: }
126:
127: ///
128: /// 当订阅者接收到事件，该做什么反应
129: /// 也就是常说的事件处理逻辑
130: ///
131: ///
132: ///
133: void HandleCustomEvent(object sender, CustomEventArgs e)
134: {
135: Console.WriteLine(id + " received this message: {0}", e.Message);
136: }
137: }
138:
139: class Program
140: {
141: static void Main(string[] args)
142: {
143: //实例一个发布者
144: Publisher pub = new Publisher();
145: //实例两个订阅者sub1,sub2,他们计划收听pub
146: Subscriber sub1 = new Subscriber("sub1", pub);
147: Subscriber sub2 = new Subscriber("sub2", pub);
148:
149: //发布者通过DoSomething触发事件，开始发布信息
150: pub.DoSomething();
151:
152: Console.WriteLine("Press Enter to close this window.");
153: Console.ReadLine();
154: }
155: }
156: }
