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

namespace 自定义标准事件
{
    class Program
    {
        static void Main(string[] args)
        {
            Publisher publisher = new Publisher();
            Subscriber subscriber = new Subscriber("subscriber",publisher);
            Subscriber2 subscriber2 = new Subscriber2("subscriber2", publisher);
            //调用引发事件的方法
            publisher.DoSomething();
            Console.Read();
        }
    }

    /// <summary>
    /// 事件的定义和调用,触发事件也可以写在这里面。
    /// 系统自带一个委托EventHandler, 可以直接使用
    /// </summary>
    class Publisher   //[发布者]
    {
        public event EventHandler<CustEventArgs> CustomEvent; //利用系统的委托定义一个事件
        
        public void DoSomething()
        {
            //调用之前可以在这里写一些其东西
            OnCustomEvent(new CustEventArgs("我是事件参数"));
        }
        /// <summary>
        /// 在受保护的虚方法中包装事件的调用，这样就允许派生类重写调用的行为
        /// </summary>
        /// <param name="e"></param>
        protected virtual void OnCustomEvent(CustEventArgs e)
        {
            CustomEvent?.Invoke(this, e);
        }
    }
    /// <summary>
    /// 事件订阅者：事件方法编琯和订阅功能
    /// </summary>
    class Subscriber
    {
        /// <summary>
        /// 带参构造 
        /// 订阅的动作写在这里，所以才要传过来发布者
        /// </summary>
        /// <param name="str"></param>
        /// <param name="publisher"></param>
        public Subscriber(string str, Publisher publisher) 
        {
            this.Str = str;
            //订阅事件
            publisher.CustomEvent += HanderCustomEvent;
        }
        private readonly string Str;
        private void HanderCustomEvent(object sender, CustEventArgs e)
        {
            //
            Console.WriteLine($"发布者:{sender.GetType()},订阅者：{Str}， 参数：{e.Message}");
        }
    }
    class Subscriber2
    {
        /// <summary>
        /// 带参构造 
        /// 订阅的动作写在这里，所以才要传过来发布者
        /// </summary>
        /// <param name="str"></param>
        /// <param name="publisher"></param>
        public Subscriber2(string str, Publisher publisher)
        {
            this.Str = str;
            //订阅事件
            publisher.CustomEvent += HanderCustomEvent;
        }
        private readonly string Str;
        private void HanderCustomEvent(object sender, CustEventArgs e)
        {
            //
            Console.WriteLine($"发布者:{sender.GetType()},订阅者：{Str}， 参数：{e.Message}");
        }
    }

    public class CustEventArgs : EventArgs
    {
        public CustEventArgs(string  message)
        {
            this.Message = message;
        }

        public string Message { get; set; }
    }
}