.Net学习之基于委托、事件的观察者模式

 /// <summary>
    /// 猫类
    /// </summary>
    public class Cat
    {
        //委托声明
        public delegate void Miaowhandler(Object sender, MiaowEventArgs e);
        //事件声明
        public event Miaowhandler MiaowEvent;

        private string MiaowStr = string.Empty;
        //自定义参数信息
        public class MiaowEventArgs : EventArgs
        {
            public readonly string MiaowStr;
            public MiaowEventArgs(string miaowStr)
            {
                this.MiaowStr = miaowStr;
            }
        }
        //猫叫
        public void Miaow()
        {
            this.MiaowStr = "瞄瞄瞄瞄瞄瞄~~~~";
            Console.WriteLine(this.MiaowStr);
        }

        public void OnMiaow(MiaowEventArgs e)
        {
            if (MiaowEvent != null)
                MiaowEvent(this, e);
        }

        public void MakeMiaow()
        {
            this.MiaowStr = "猫睡着了";
            Console.WriteLine(MiaowStr);
            Thread.Sleep(2000);
            this.MiaowStr = "猫醒了";
            Console.WriteLine("猫醒了");
            Thread.Sleep(500);
            Miaow();
            Thread.Sleep(1000);
            MiaowEventArgs e =new MiaowEventArgs(this.MiaowStr);
            OnMiaow(e);
        }
    }