看懂 ，學會 .NET 事件的正確姿勢-簡單版

      發現之前寫了一篇關於事件的闡述寫的過於抽象。現在想想先理解本質由簡入難比較合適
  之前的一篇博客地址：https://www.cnblogs.com/LiMin/p/7212217.html

 參照網上例子給個簡單版本的如下：貓叫->老鼠跑了->主人醒了

using System;

namespace EventTest
{
    public class EventDemo
    {
        public void EventTest()
        {
            Cat cat = new Cat();
            Mouse ms = new Mouse();
            Master mas = new Master();
            cat.Calling += ms.Escape;//老鼠對 clling 訂閱
            cat.Calling += mas.Wakened;//人 對 calling 訂閱
            cat.Call(); //貓叫
        }
    }
    public sealed class Cat
    {
        public event EventHandler Calling;
        public void Call()
        {
            Console.WriteLine("貓叫了...");
            Calling?.Invoke(this, EventArgs.Empty);
        }
    }
    public sealed class Mouse : EventArgs
    {
        public void Escape(object sender, EventArgs e)
        {
            Console.WriteLine("老鼠逃跑了...");
        }
    }
    public sealed class Master
    {
        public void Wakened(object sender, EventArgs e)
        {
            Console.WriteLine("主人醒了");
        }
    }
}