委托

namespace DelegateDemo
{
    delegate  void HeaterDelegate(int t);

    class Heater
    {
        private int temperature;
        // 烧水 
        //给委托heaterDel加上事件修饰符
         //event:事件，事件：是被event关键字修饰的委托变量，被event关键字修饰的委托变量，在类的外部只能出现在+=的左侧。也就是只能在类的外部被挂载方法，而不能直接调用
        public event HeaterDelegate heaterDel;

        public void BoilWater()
        {
            for (int i = 0; i <= 100; i++)
            {
                temperature = i;
                if (i >= 90)
                {
                    if (heaterDel != null)
                    {
                        heaterDel(temperature);
                    }
                }
            }
        }
    }
     abstract class LongXia
    {
        public abstract void Tongzhi(int t);
    }
     class Longzi:LongXia
    {
        string name;
        public Longzi(string n)
        {
            name = n;
        }
        Display d = new Display();
        public override void Tongzhi(int wendu)
        {
            d.ShowMsg(wendu, name);
        }
    }
        class Display
    {
        public void ShowMsg(int param, string n)
        {
            Console.WriteLine("Display：水已烧开，当前温度：{0}度。{1}同志", param, n);
        }
    }
    class Alarm
    {
        public void MakeAlert(int param, string who)
        {
            Console.WriteLine("Alarm：嘀嘀嘀，水已经 {0} 度了：{1}同志", param, who);
        }
    }
    class Xiazi:LongXia
    {
        private string name;
        Alarm a = new Alarm();
        public Xiazi(string n)
        {
            this.name = n;
        }
        public override void Tongzhi(int wendu)
        {
            a.MakeAlert(wendu, name);
        }
    class Program
    {
       
        //////////////////////////////////////////////

        static void Main(string[] args)
        {
            Longzi xiaoluobutou = new Longzi("萝卜头");
            Longzi luobutou = new Longzi("萝卜头");

            Xiazi xia = new Xiazi("看不见");

            Heater h = new Heater();

           

            //h.heaterDel = xiaoluobutou.Tongzhi;
            h.heaterDel += xiaoluobutou.Tongzhi;
            h.heaterDel += luobutou.Tongzhi;
            h.heaterDel += xia.Tongzhi;

           
            h.BoilWater();

            //存在在热水器外面调用通知的可能的问题得到解决。
            h.heaterDel(100);
        }
    }
    }
}