使用.NET的WeakEventManager实现弱事件的示例

using System;
using System.Windows;

public class MyEventSource
{
    // 定义一个事件
    public event EventHandler<MyEventArgs> MyEvent;

    // 触发事件的方法
    public void RaiseEvent()
    {
        // 使用WeakEventManager来触发事件
        WeakEventManager<MyEventSource, MyEventArgs>.RaiseEvent(
            this, new MyEventArgs("Event raised"), nameof(MyEvent));
    }
}

public class MyEventArgs : EventArgs
{
    public string Message { get; }

    public MyEventArgs(string message)
    {
        Message = message;
    }
}

public class MyEventHandler
{
    // 事件处理程序
    public void HandleEvent(object sender, MyEventArgs e)
    {
        Console.WriteLine(e.Message);
    }
}

public class Program
{
    public static void Main()
    {
        MyEventSource eventSource = new MyEventSource();
        MyEventHandler eventHandler = new MyEventHandler();

        // 使用WeakEventManager订阅事件
        WeakEventManager<MyEventSource, MyEventArgs>.AddHandler(
            eventSource, nameof(eventSource.MyEvent), eventHandler.HandleEvent);

        // 触发事件
        eventSource.RaiseEvent();

        // 取消订阅事件
        WeakEventManager<MyEventSource, MyEventArgs>.RemoveHandler(
            eventSource, nameof(eventSource.MyEvent), eventHandler.HandleEvent);
    }
}