设计模式——观察者模式

设计模式——观察者模式

观察者模式 定义了一种一对多的依赖关系，让多个观察者对象同时监听某一个主题对象，这个主题对象在状态发生变化时，会通知所有观察者对象，使他们能够自动更新自己

 ///看股票的同事
    class StockObserver
    {
        private string name;
        private Subject sub;

        public StockObserver(string name, Subject sub)
        {
            this.name = name;
            this.sub = sub;
        }
        //关闭股票行情
        public void CloseStockMarket()
        {
            Console.WriteLine("{0} {1} 关闭股票行情，继续工作！",sub.SubjectState,name);
        }
    }
    //看NBA 的同事
    class NBAObserver
    {
        private string name;
        private Subject sub;

        public NBAObserver(string name, Subject sub)
        {
            this.name = name;
            this.sub = sub;
        }
        //关闭股票行情
        public void CloseNBADirectSeeding()
        {
            Console.WriteLine("{0} {1} 关NBA直播，继续工作！", sub.SubjectState, name);
        }
    }

    //通知者接口
    interface Subject
    {
        void Notify();

        string SubjectState
        {
            get;
            set;
        }
    }

    delegate void EventHandler();

    //老板类 
    class Boss : Subject
    {
        //声明一事件Update，类型为委托EventHandler
        public event EventHandler Update;

        private string action;
        public string SubjectState { get { return action; } set { action = value; } }

        public void Notify()
        {
            Update();//在访问“通知”方法时，调用“更新”
        }
    }

    //前台秘书类

    class Secretary:Subject
    {
        //声明一事件Update，类型为委托EventHandler
        public event EventHandler Update;

        private string action;
        public string SubjectState { get { return action; } set { action = value; } }

        public void Notify()
        {
            Update();//在访问“通知”方法时，调用“更新”
        }
    }
         static void Main(string[] args)
        {
                    //老板胡汉三
            Boss huhansan = new Boss();
            //看股票的同事
            StockObserver tongshi1 = new StockObserver("魏关在", huhansan);
            //看NBA的同事
            NBAObserver tongshi2 = new NBAObserver("易管查", huhansan);

            huhansan.Update += new 观察者模式.EventHandler(tongshi1.CloseStockMarket);
            huhansan.Update += new 观察者模式.EventHandler(tongshi2.CloseNBADirectSeeding);

            //老板回来
            huhansan.SubjectState = "我胡汉三回来了";

            //发出通知
            huhansan.Notify();
        }

标签：EventHandler,sub,string,观察者,模式,Update,设计模式,public,name
来源： https://blog.csdn.net/weixin_43945471/article/details/111383613