C# 委托还能这样用

    public interface ISubjectwhere T : class
    {
        /// 

        /// 
        /// 
        /// 为true表示注册，false表示注销
        int RegistNotify(bool action, IObserver ob);
    }

    public interface IObserverwhere T : class
    {
        void MessageNotify(T message);
    }

    class Observer : ObserverPattern.IObserver
    {
        public Observer(ISubject sub)
        {
            sub.RegistNotify(true, this);  // 注册
        }

        void ObserverPattern.IObserver.MessageNotify(Msg message)
        {
            DateTime cur = DateTime.Now;  // 当接收到通知时记录下当前时间
            Debug.WriteLine("s : " + cur.Second + " ms : " + cur.Millisecond);
        }
    }

    public partial class Form1 : Form, ISubject
    {
        List> m_observers;

        public Form1()
        {
            InitializeComponent();
            this.Load += Form1_Load;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            m_observers = new List>();

            Observer ob = new Observer(this);
            Observer ob2 = new Observer(this);
            Observer ob3 = new Observer(this);
            Observer ob4 = new Observer(this);
            Observer ob5 = new Observer(this);
            Observer ob6 = new Observer(this);
            Observer ob7 = new Observer(this);
            Observer ob8 = new Observer(this);
            Observer ob9 = new Observer(this);
            Observer ob10 = new Observer(this);
            Observer ob11 = new Observer(this);
            Observer ob12 = new Observer(this);
            Observer ob13 = new Observer(this);
            Observer ob14 = new Observer(this);
            Observer ob15 = new Observer(this);
            Observer ob16 = new Observer(this);
            Observer ob17 = new Observer(this);
        }

        int ISubject.RegistNotify(bool action, ObserverPattern.IObserver ob)
        {
            if (action) { m_observers.Add(ob); return 0; }
            m_observers.Remove(ob);
            return 0;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Msg message = new Msg() { Ident = 1, Data = null };

            foreach (var ob in m_observers)
            {
                Task.Factory.StartNew(() => ob.MessageNotify(message));
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Msg message = new Msg() { Ident = 2, Data = null };

            foreach (var ob in m_observers)
            {
                new Thread(() => { ob.MessageNotify(message); }) { IsBackground = true, }.Start();
            }
        }

    }
}