事件Event

using System;
using System.Runtime.Serialization;
using static System.Console;
namespace Event03
{
    class Program
    {
        static void Main(string[] args)
        {
            Judgment judgment=new Judgment();
            RunSporters sporters=new RunSporters();
            judgment.eventRun += sporters.Run;
            judgment.eventRun += sporters.RunFail;
            judgment.Begin();
            ReadKey();
        }

    }

    //发布器（publisher） 是一个包含事件和委托定义的对象。事件和委托之间的联系也定义在这个对象中。
    class Judgment
    {
        public delegate void delegateRun();

        public event delegateRun eventRun;

        public void Begin()
        {
            eventRun?.Invoke();
        }
    }

    //订阅者
    public class RunSporters
    {
        public void Run()
        {
            WriteLine("运动员跑起来了");
        }

        public void RunFail()
        {
            WriteLine("有一个起跑失败");
        }
    }

}

02.标准事件

public delegate void EventHandler(Object sender, EventArgs e);

1.第一个参数sender 用来保存触发事件的对象的引用。由于是Object类型的，所以可以匹配任何类型的实例。

2.第二个参数用来保存有该事件相关的信息

通过扩展EventArgs来传递数据

using System;
using System.Runtime.Serialization;
using static System.Console;
namespace Event03
{
    class Program
    {
        static void Main(string[] args)
        {
           CarDealer carDealer=new CarDealer();
           Consumer consumer=new Consumer("一休");
           carDealer.CarEvent += consumer.ConsumerReply;
           carDealer.RaiseCarInfo("宝马");
           ReadKey();
        }

    }

    public class CarInfoEventArgs:EventArgs
    {
        public string Car { get; set; }

        public CarInfoEventArgs(string car)
        {
            this.Car = car;
        }
    }

    public class CarDealer
    {
        public event EventHandler<CarInfoEventArgs> CarEvent;

        public void RaiseCarInfo(string car)
        {
            WriteLine($"new car {car}");
            //EventHandler委托的两个参数，第一个参数就是触发事件的事件对象
            CarEvent?.Invoke(this,new CarInfoEventArgs(car));
        }

    }

    public class Consumer
    {
        public string Name;

        public Consumer(string name)
        {
            this.Name = name;
        }

        //事件处理程序，注意参数和事件的委托EventHandler<CarInfoEventArgs>一样
        public void ConsumerReply(object sender,CarInfoEventArgs e)
        {
            WriteLine($"{Name}:car{e.Car} is Very good!");
        }
    }


}

标准事件

using System;
using System.Collections.Generic;
using System.Threading;
using static System.Console;
namespace Event07
{
    public delegate void BirthDayEventHandler(object sender,BirthdayEventArgs e);
    class Program
    {
        static void Main(string[] args)
        {

            Me me=new Me("一休");

            Friend1 friend1=new Friend1();
            Friend2 friend2 = new Friend2();

            //订阅事件
            me.birthDayEvent+=new BirthDayEventHandler(friend1.SendGift);
            me.birthDayEvent += new BirthDayEventHandler(friend2.SendGift);
            me.TimeUp();
            ReadKey();
        }
      
    }

    public class BirthdayEventArgs : EventArgs
    {
        public string Name { get; set; }

        public BirthdayEventArgs(string Name)
        {
            this.Name = Name;
        }
    }


    public class Me 
    {
        public event BirthDayEventHandler birthDayEvent;

        private string name;
        public Me(string name)
        {
            this.name = name;
        }

        //发布事件
        public void TimeUp()
        {
            birthDayEvent?.Invoke(this, new BirthdayEventArgs(name));
        }

    }


    public class Friend1
    {
        public void SendGift(object sender, BirthdayEventArgs e)
        {
            Console.WriteLine(e.Name + " 生日到了，我要送礼物");
        }
    }
    public class Friend2
    {
        public void SendGift(object sender, BirthdayEventArgs e)
        {
            Console.WriteLine(e.Name + " 生日到了，我要送荔湾");
        }
    }
}

事件是一个委托链

// 1. 一个被初始化为null的私有委托字段

private BirthDayEventHandle BirthDayEvent =null;

//2\. 一个公共add_BirthDayEvent方法
    public void add_BirthDayEvent(BirthDayEventHandle value)
    {
        // 以一种线程安全的方式从事件中添加一个委托
    }
    // 3\. 一个公共的remove_BirthDayEvent方法
    public void remove_BirthDayEvent(BirthDayEventHandle value)
    {
        // 以一种线程安全的方式从事件中移除一个委托
    }