如何在C＃.NET表单上捕获按键

Question

I have a parent form that contains a lot of controls. What I am trying to do is filter all of the key presses for that form. The trouble is that if the focus is on one of the controls on the form then the parent form is not getting the key press event, so how do I capture the key down event?

Answer 1

在表单上将KeyPreview设置为true，您将捕获它们： MSDN

Answer 2

This will only work on form, but not if any other component is in focus

public partial class ChildForm : Form
{

    public ChildForm()
    {       
       KeyPress += KeyPressHandler;
    }

    public KeyPressHandler(object sender, KeyPressEventArgs e)
    {
       if (_parent != null)
       {
           _parent.NotifyKeyPress(e);
       } 
    }
}

This will work even when other components are in focus

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
    if (keyData == Keys.F1)
    {
        MessageBox.Show("You pressed the F1 key");
        return true;    // indicate that you handled this keystroke
    }

    // Call the base class
    return base.ProcessCmdKey(ref msg, keyData);
}