1/*
2
* 题目：
3 * 猫叫了，所有老鼠开始逃跑，主人被惊醒，请用OO的思想描绘此过程
4 * 1，老鼠跟主人是被动的
5 * 2，要考虑联动性与扩展性
6
*/
7
using System;
8using System.Collections.Generic;
9using System.Text;
10
11namespace CatCry {
12
13
/*委托，当猫叫时将信息传给所有观察者*/
14 public delegate void CatCryEventHandler(object sender, EventArgs e);
15
16 /*被观察对象*/
17 abstract class Subject {
18 public event CatCryEventHandler CatCryEvent;//猫叫时的事件
19 public void Cry(EventArgs e) {
20 this.CatCryEvent(this, e);
21
}
22 public void Cry() {
23 //不接收猫叫时发出的信息
24 this.CatCryEvent(this, new EventArgs());
25 }
26 }
27
28 /*观察者*/
29 abstract class Observer {
30 public Observer() { }
31 public Observer(Subject subject) {
32 subject.CatCryEvent += new CatCryEventHandler(this.Notified);
33 }
34 //当猫叫时做出的反应（当收到通知时）
35 abstract protected void Notified(object sender, EventArgs e);
36 }
37
38 /*定义猫作为被观察对象*/
39 class Cat : Subject {
40 public Cat() { Console.WriteLine("猫叫了"); }
41 }
42
43 /*定义老鼠作为观察者*/
44 class Mouse : Observer {
45 string mouseName;
46 public Mouse() { }
47 public Mouse(string mouseName, Subject subject)
48 : base(subject) {
49 this.mouseName = mouseName;
50 }
51 override protected void Notified(object sender, EventArgs e) {
52 Console.WriteLine(this.mouseName + "开始逃跑");
53 }
54 }
55
56 /*定义主人作为观察者*/
57 class Marster : Observer {
58 public Marster() { }
59 public Marster(Subject subject) : base(subject) { }
60 override protected void Notified(object sender, EventArgs e) {
61 Console.WriteLine("主人被惊醒了");
62 }
63 }
64
65 /// <summary>
66 /// 功能：用观察者模式实现
67 /// 作者：allnen
68 /// 时间：2008-6-5
69 /// </summary>
70 class Program {
71 static void Main(string[] args) {
72 Cat cat = new Cat();
73 Mouse m1 = new Mouse("老鼠1", cat);
74 Mouse m2 = new Mouse("老鼠2", cat);
75
76 Marster marster = new Marster(cat);
77 cat.Cry();//猫叫了
78
79 }
80 }
81}
code 烧开水
using System;
using System.Collections.Generic;
using System.Text;
namespace Delegate {
// 热水器
public class Heater {
private int temperature;
public string type = "RealFire 001"; // 添加型号作为演示
public string area = "China Xian"; // 添加产地作为演示
//声明委托
public delegate void BoiledEventHandler(Object sender, BoiledEventArgs e);
public event BoiledEventHandler Boiled; //声明事件
// 定义BoiledEventArgs类，传递给Observer所感兴趣的信息
public class BoiledEventArgs : EventArgs {
public readonly int temperature;
public BoiledEventArgs(int temperature) {
this.temperature = temperature;
}
}
// 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
protected virtual void OnBoiled(BoiledEventArgs e) {
if (Boiled != null) { // 如果有对象注册
Boiled(this, e); // 调用所有注册对象的方法
}
}
// 烧水。
public void BoilWater() {
for (int i = 0; i <= 100; i++) {
temperature = i;
if (temperature > 95) {
//建立BoiledEventArgs 对象。
BoiledEventArgs e = new BoiledEventArgs(temperature);
OnBoiled(e); // 调用 OnBolied方法
}
}
}
}
// 警报器
public class Alarm {
public void MakeAlert(Object sender, Heater.BoiledEventArgs e) {
Heater heater = (Heater)sender; //这里是不是很熟悉呢？
//访问 sender 中的公共字段
Console.WriteLine("Alarm：{0} - {1}: ", heater.area, heater.type);
Console.WriteLine("Alarm: 嘀嘀嘀，水已经 {0} 度了：", e.temperature);
Console.WriteLine();
}
}
// 显示器
public class Display {
public static void ShowMsg(Object sender, Heater.BoiledEventArgs e) { //静态方法
Heater heater = (Heater)sender;
Console.WriteLine("Display：{0} - {1}: ", heater.area, heater.type);
Console.WriteLine("Display：水快烧开了，当前温度：{0}度。", e.temperature);
Console.WriteLine();
}
}
class Program {
static void Main() {
Heater heater = new Heater();
Alarm alarm = new Alarm();
heater.Boiled += alarm.MakeAlert; //注册方法
heater.Boiled += (new Alarm()).MakeAlert; //给匿名对象注册方法
heater.Boiled += new Heater.BoiledEventHandler(alarm.MakeAlert); //也可以这么注册
heater.Boiled += Display.ShowMsg; //注册静态方法
heater.BoilWater(); //烧水，会自动调用注册过对象的方法
}
}
}
输出为：
Alarm：China Xian - RealFire 001:
Alarm: 嘀嘀嘀，水已经 96 度了：
Alarm：China Xian - RealFire 001:
Alarm: 嘀嘀嘀，水已经 96 度了：
Alarm：China Xian - RealFire 001:
Alarm: 嘀嘀嘀，水已经 96 度了：
Display：China Xian - RealFire 001:
Display：水快烧开了，当前温度：96度。