事件委托
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
public delegate void BoiledEventHandler(Object sender, BoiledEventArgs e); //声明委托
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 OnBolied(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) {
BoiledEventArgs e = new BoiledEventArgs(temperature);
OnBolied(e);
}
}
}
}
// 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
}
}
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