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();
 }
 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();
 }
        public void Run()
        {
            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
        }