class Program
{
        static void Main(string[] args)
    {
      　XiaoBai xiaobai = new XiaoBai();
        //Google公司
        ItCompany google = new ItCompany("谷歌中國", "CTO", xiaobai);
        //微軟公司
        ItCompany microsoft = new ItCompany("微軟中國", "架構師", xiaobai);
        //花旗銀行
    FinanceCompany AmericaBank = new FinanceCompany("花旗銀行", "金融分析師", xiaobai);
        //委托的好處，可以應用于不同的類的不同方法
        //方法“委托”給委托，委托“委托”給事件
        //委托類型與事件聲明時的委托類型相同
        //因為是傳引用，所以方法后面不能帶括號，帶括號則是調用方法了
        //一個委托可以搭載多個方法，一個事件則擁有一個委托鏈
        xiaobai.Update += new TheEventHandler(google.ComeToItCompany);
        xiaobai.Update += new TheEventHandler(microsoft.ComeToItCompany);
        xiaobai.Update += new TheEventHandler(AmericaBank.ComeToFinanceCompany);
        xiaobai.SubjectState = "我小白過來應聘職位啦！";
        //發出通知，觸發事件
        xiaobai.Notify();
        //以下代碼與上面相似
        XiaoHua xiaohua = new XiaoHua();
        ItCompany microsoft2 = new ItCompany("微軟總公司", "CEO", xiaohua);
    FinanceCompany ChinaBank = new FinanceCompany("中國央行", "財務部總經理", xiaohua);
        xiaohua.Update += new TheEventHandler(microsoft2.ComeToItCompany);
        xiaohua.Update += new TheEventHandler(ChinaBank.ComeToFinanceCompany);
        xiaohua.SubjectState = "我小華過來應聘職位啦！";
        xiaohua.Notify()
        Console.ReadLine();
    }
}
//通知者接口
interface Subject
{
    void Notify();

string SubjectState
    {
        get;
        set;
    }
}
 //事件處理程序的委托，相當于一個類（在編譯成IL后確確實實是類）或者方法指針，
與常規類定義不同，帶參數和返回值
    delegate void TheEventHandler();
//小白
class XiaoBai : Subject
{
    //聲明一事件Update，類型為委托TheEventHandler
    public event TheEventHandler Update;
    private string action; //用Notify方法觸發事件
    public void Notify()
    {
        Update();
    }
    public string SubjectState
    {
        get { return action; }
        set { action = value; }
    }
}
//小華
class XiaoHua : Subject
{
    //聲明一事件Update，類型為委托TheEventHandler
    public event TheEventHandler Update;
    private string action;
    //用Notify方法觸發事件
    public void Notify()
    {
        Update();
    }
    public string SubjectState
    {
        get { return action; }
        set { action = value; }
    }
}
//IT行業
class ItCompany
{
    private string companyname;
    private string job;
    private Subject sub;

    public ItCompany(string _companyname, string _job, Subject _sub)
    {
        companyname = _companyname;
        job = _job;
        sub = _sub;
    }
    //參數和返回值與委托TheEventHandler一致
    public void ComeToItCompany()
    {
        Console.WriteLine("{0} {1}： 來我們公司做{2}！", sub.SubjectState, 
companyname, job);
    }
}
//金融行業
class FinanceCompany
{
    private string companyname;
    private string job;
    private Subject sub;

        public FinanceCompany(string _companyname, string _job, Subject _sub)
    {
        companyname = _companyname;
        job = _job;
        sub = _sub;
    }
//參數和返回值與委托TheEventHandler一致
    public void ComeToFinanceCompany()
    {
        Console.WriteLine("{0} {1}： 來我們公司做{2}！", sub.SubjectState, 
companyname, job);
    }
}