C# 创建一个事件

在C#中创建一个事件，需要以下步骤：

1. 声明事件的委托类型

public delegate void MyEventHandler(object sender, EventArgs e);

2. 声明事件

public event MyEventHandler MyEvent;

3. 触发事件

if (MyEvent != null)
{
    MyEvent(this, EventArgs.Empty);
}

完整示例：

using System;

public delegate void MyEventHandler(object sender, EventArgs e);

class MyClass
{
    public event MyEventHandler MyEvent;

    public void DoSomething()
    {
        Console.WriteLine("Do something...");
        OnMyEvent();
    }

    protected virtual void OnMyEvent()
    {
        if (MyEvent != null)
        {
            MyEvent(this, EventArgs.Empty);
        }
    }
}

class Program
{
    static void Main(string[] args)
    {
        MyClass myObject = new MyClass();
        myObject.MyEvent += MyEventHandlerMethod;

        myObject.DoSomething();

        Console.ReadKey();
    }

    static void MyEventHandlerMethod(object sender, EventArgs e)
    {
        Console.WriteLine("MyEventHandlerMethod called.");
    }
}