委托对观察者模式的改进

分析详见：http://lvxingzhelimin.blog.163.com/blog/static/1707165502011101655652697/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            //老板胡汉三
            Boss huhansan = new Boss();
            //看股票的同事
            StockObserver tongshi1 = new StockObserver("魏关拆", huhansan);
            NBAObserver tongshi2 = new NBAObserver("易观查", huhansan);

            //将“看股票者”的“关闭程序”方法和“看NBA者”的“关闭直播”的方法，
            //挂钩到“老板”的“更新”上，也就是将两个不同的类的不同方法委托给“老板”类的“更新”了。
            huhansan .Update +=new EventHandler( tongshi1 .CloseStockMarket );
            huhansan .Update += new EventHandler( tongshi2 .CloseNBADirectoSeeding );

            //老板回来
            huhansan.SubjectState = "我胡汉三又回来了！";
            //发出通知
            huhansan.Notify();

            Console.Read();
        }
    }
}
//通知者接口
interface Subject
{    
    void Notify();
    string SubjectState
    {
        get;
        set;
    }
}

//声明一个委托
delegate void EventHandler();


//老板类
class Boss : Subject
{
    //声明一个事件Update，类型为EventHandler
    public event EventHandler Update;

    private string action;

    //在访问“通知”方法时，调用“更新”
    public void Notify()
    {
        Update();
    }
    //老板类的状态
    public string SubjectState
    {
        get { return action; }
        set { action = value; }
    }
}

//前台类
class Secretary : Subject
{
    //在前台类中声明一个委托事件，名称叫Update
    public event EventHandler Update;

    private string action;

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

    //前台类的状态
    public string SubjectState
    {
        get { return action; }
        set { action = value; }
    }
}



//看股票的同事
class StockObserver 
{
    private string name;
    private Subject sub;
    //首先建立与继承的父类的最基本的属性设置
    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;
    }

    public void CloseNBADirectoSeeding()
    {
        Console.WriteLine("{0}{1}关闭NBA，继续工作！", sub.SubjectState, name);
    }
}