从父级引发用户控件的事件

Question

我有一个具有以下重写事件的用户控件：

protected override void OnKeyDown(KeyEventArgs e)
{
    if (e.KeyCode == Keys.Left )
        DoSomething();
}

当我将用户控件放在我的主窗体上时，不会触发此事件。
如何从父表单访问此事件？

protected override void OnKeyDown(KeyEventArgs e)
{
    e.Handled = true;
    if (e.KeyCode == Keys.Left)
        Move(pt.X,pt.Y);//Move is a function within the usercontrol
    else if (e.KeyCode == Keys.Right)
        Move(pt.X,pt.Y);
   //other conditions
   e.Handled = false;
}

我需要父母在这个事件上得到通知

Answer 1

根据您发布的更新的问题和代码示例，如果您希望通知父表单发生移动操作，则需要在UserControl中创建一个事件并在父表单中订阅它。 这可以通过以下示例实现。 如果这可以解决您的问题，请告诉我，否则请发布更多详细信息。

最好的祝福

// Define custom EventArgs to pass into the Move event
public class MoveEventArgs : EventArgs
{
    private Point _movePoint;
    public MoveEventArgs(Point movePoint)
    {
        _movePoint = _movePoint;
    }

    public Point MovePoint { get { return _movePoint; } } 
}

// Define a custom user control that raises an event to subscribers on move
public class MyUserControl : UserControl
{
    public event EventHandler<MoveEventArgs> Moved;

    protected override void OnKeyDown(KeyEventArgs e)
    {
        e.Handled = true;
        if (e.KeyCode == Keys.Left)
        {
            Move(pt.X,pt.Y);//Move is a function within the usercontrol
            OnMoved(pt);
        }   
        else if (e.KeyCode == Keys.Right)
        {
            Move(pt.X,pt.Y);
            OnMoved(pt);
        }
       //other conditions
       e.Handled = false;
    }

    // Raises a custom event, Moved 
    protected void OnMoved(Point movePoint)
    {
        var handler = Moved;
        if (handler != null)
        {
            handler(this, new MoveEventArgs(movePoint);
        }
    }
}

// How to subscribe to the event (and be notified of move)
public class MyParentForm : Form
{
    public MyParentForm()
    {
        InitializeComponent();
        _myUserControl.Moved += new EventHandler<MoveEventArgs>(MyUserControl_Moved);
    }

    private void MyUserControl_Moved(object sender, MoveEventArgs e)
    {
        // e.MovePoint now contains the point that the usercontrol was moved to
        // this event will fire whenever the user presses Left or Right arrow
    }
}

Answer 2

如果我理解正确，您试图从父窗体中调用用户控件的OnKeyDown方法。
这是主要的表单类：

public class Form1 : Form
{
    private UserControl1 myControl;

    public Form1()
    {
        myControl = new UserControl1();
        Controls.Add(myControl);
    }

    protected override void OnKeyDown(KeyEventArgs e)
    {
        base.OnKeyDown(e);
        myControl.InvokeOnKeyDown(e);
    }
}

这是用户控件：

public class UserControl1 : UserControl
{
    protected override void OnKeyDown(KeyEventArgs e)
    {
        base.OnKeyDown(e);
        MessageBox.Show("Key Down Fired!");
    }

    public void InvokeOnKeyDown(KeyEventArgs e)
    {
        OnKeyDown(e);
    }
}

关于箭头键的编辑：箭头键通常不被视为输入键，因此不会传递给键方法。 要更改此设置，您必须覆盖IsInputKey方法：

 protected override bool IsInputKey(Keys e)
 {
     if (e == Keys.Up || e == Keys.Down ||
         e == Keys.Left || e == Keys.Right) return true;
     return base.IsInputKey(e);
 }