C＃用户控制按钮单击事件处理程序从主窗体调用函数 [英] C# user control button click event handler to call a function from main form

问题描述

我有一个Form和一个UserControl。在我的UserControl中我有一个按钮，我想从Form中调用一个方法。任何人都可以帮助C＃？

解决方案

您需要为usercontrol的按钮事件创建一个事件处理程序，并将其从

  class MyControl：UserControl 
 {
 public delegate void ButtonClickedEventHandler（对象发件人，EventArgs e）; 
 public event ButtonClickedEventHandler OnUserControlButtonClicked; 
} 
  

现在您需要听实际按钮的事件：

  class MyControl：UserControl 
 {
 //见上面
 
 public MyControl（） 
 {
 _myButton.Click + = new EventHandler（OnButtonClicked）; 
} 
 
 private void OnButtonClicked（object sender，EventArgs e）
 {
 //将事件委托给调用者
 if（OnUserControlButtonClicked！= null ）
 OnUserControlButtonClicked（this，e）; 
} 
} 
  

从主窗体（所有者），您现在可以听对于事件：

  public FancyForm：Form 
 {
 public FancyForm（）
 { 
 _myUserControl.OnUserControlButtonClicked + = new EventHandler（OnUCButtonClicked）; 
} 
 
 private void OnUCButtonClicked（object sender，EventArgs e）
 {
 //从这里处理事件
 MessageBox.Show（Horray！ ）; 
} 
} 
  

更新：两个实现通过使用Lambdas和默认的EventHandler代理定义，甚至可以安全地使用几行代码。

  class MyControl：UserControl 
 { 
 public event EventHandler OnUserControlButtonClicked; 
 //如果要使用不同的EventArgs实现，请使用此功能：
 // public event EventHandler< CustomEventArgs> OnUserControlButtonClicked; 
 
 public MyControl（）
 {
 _myButton.Click + =（s，e）=> 
 {
 if（OnUserControlButtonClicked！= null）
 OnUserControlButtonClicked（this，e）; 
} 
} 
} 
 
 public FancyForm：Form 
 {
 public FancyForm（）
 {
 _myUserControl .OnUserControlButtonClicked + =（s，e）=>的MessageBox.show（ Horray！）; 
} 
} 
  

更新2 ：安全更多的行与C＃6的力量：

  class MyControl：UserControl 
 {
 public event EventHandler OnUserControlButtonClicked; 
 
 public MyControl（）
 {
 _myButton.Click + =（s，e）=> this.OnUserControlButtonClicked？.Invoke（this，e）; 
} 
} 
  

I have a Form and a UserControl. In my UserControl I have a button, and I would like to call a method from the Form. Can anyone help in C#?

解决方案

You need to create an event handler for the button-event of the usercontrol and fire it from the click event of the actual button.

class MyControl : UserControl
{
    public delegate void ButtonClickedEventHandler(object sender, EventArgs e);
    public event ButtonClickedEventHandler OnUserControlButtonClicked;
}

Now you need to listen to the event of the actual button:

class MyControl : UserControl
{
    // See above

    public MyControl()
    {
        _myButton.Click += new EventHandler(OnButtonClicked);
    }

    private void OnButtonClicked(object sender, EventArgs e)
    {
        // Delegate the event to the caller
        if (OnUserControlButtonClicked != null)
            OnUserControlButtonClicked(this, e);
    }
}

From the main form (owner) you can now listen to the event:

public FancyForm : Form
{
    public FancyForm()
    {
        _myUserControl.OnUserControlButtonClicked += new EventHandler(OnUCButtonClicked);
    }

    private void OnUCButtonClicked(object sender, EventArgs e)
    {
        // Handle event from here
        MessageBox.Show("Horray!");
    }
}

Update: Both implementations can even safe a few lines of code by using Lambdas and default EventHandler delegate definitions.

class MyControl : UserControl
{    
    public event EventHandler OnUserControlButtonClicked;
    // Use this, if you want to use a different EventArgs implementation:
    // public event EventHandler<CustomEventArgs> OnUserControlButtonClicked; 

    public MyControl()
    {
        _myButton.Click += (s, e) => 
        {
            if (OnUserControlButtonClicked != null)
                OnUserControlButtonClicked(this, e);
        }
    }
}

public FancyForm : Form
{
    public FancyForm()
    {
        _myUserControl.OnUserControlButtonClicked += (s, e) => MessageBox.Show("Horray!");
    }
}

Update 2: Safe even more lines with the power of C# 6:

class MyControl : UserControl
{    
    public event EventHandler OnUserControlButtonClicked;

    public MyControl()
    {
        _myButton.Click += (s, e) => this.OnUserControlButtonClicked?.Invoke(this, e);
    }
}

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