//热水器    public class Heater {        public delegate void BoilHandler(int param);        public event BoilHandler BoilEvent;        //水温        private int temperature;        //烧水        public void BoilWater() {            for (int i = 0; i <= 100; i++) {                temperature = i;                if (temperature > 95) {                    BoilEvent(temperature);                }            }        }    }

 //警报器    public class Alarm {        //发出警报        public static void MakeAlert(int param) {            Console.WriteLine("Alarm：水已经{0}度了",param);        }    }

 //显示器    public class Display {        //显示温度        public static void ShowMsg(int param)        {            Console.WriteLine("Display：水快烧开，当前温度：{0}度",param);        }    }

 class Program    {        static void Main(string[] args)        {            Heater heater = new Heater();            heater.BoilEvent += Alarm.MakeAlert;            heater.BoilEvent += Display.ShowMsg;            heater.BoilWater();        }    }