C#，如何创建一个事件并在另一个类中侦听它? [英] C#, How to create an event and listen for it in another class?

问题描述

我不知道如何执行此操作，这是示例代码.我想做的事.

I can't figure out how to do this, heres sample code. Of what I wish to do.

public Class MainForm : Form
{
    MyUserControl MyControl = new MyUserControl;
    private void Button_Click(object sender, EventArgs e)
    {
        //Create MyEvent
    }    
}

public Class MyUserControl : UserControl
{
    //listen for MyEvent from MainForm, and perform MyMethod
    public void MyMethod()
    {
         //Do Stuff here
    }
}

推荐答案

第1步)在MainForm上公开一个事件……说.

Step 1) Expose an event on MainForm... say..

public event Action simpleEvent

第2步)给MyUserControl一个构造函数，该构造函数采用MainForm的一个实例并将一个操作绑定到该事件

Step 2) Give MyUserControl a constructor that takes an instance of MainForm and bind an action to that event

public MyUserControl(MainForm form) {
    form += () => Console.WriteLine("We're doing something!")
}

第3步)在MainForm.Button_Click中引发事件

Step 3) raise the event in MainForm.Button_Click

if(simpleEvent != null) simpleEvent();

注意:您可以注册自己的委托并使用lambda表达式以外的其他东西.请参阅 http://msdn.microsoft.com/en-us/library/17sde2xt.aspx 以获得更详尽的解释

Note: You could register your own delegates and work with something other than lambda expressions. See http://msdn.microsoft.com/en-us/library/17sde2xt.aspx for a more thorough explanation

您的最终结果将看起来像...

Your end result would look like...

public Class MainForm : Form
{
    public event Action MyEvent;

    MyUserControl MyControl = new MyUserControl(this);
    private void Button_Click(object sender, EventArgs e)
    {
        if(simpleEvent != null) simpleEvent();
    }    
}

public Class MyUserControl : UserControl
{
    //listen for MyEvent from MainForm, and perform MyMethod
    public MyUserControl(MainForm form) {
        simpleEvent += () => MyMethod();
    }

    public void MyMethod()
    {
         //Do Stuff here
    }
}

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