KeyPress on entire form, not just one object?

Question

I'm working on making pong in C#, and I've come across a problem. I have KeyPreview on, and here's my code

private void Form1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == (char)Keys.Up || e.KeyChar == (char)Keys.W) {
        picPaddle.Top -= 10;
    }
    else if (e.KeyChar == (char)Keys.Down || e.KeyChar == (char)Keys.S) {
        picPaddle.Top += 10;
    }
}

When I press any of the keys, nothing happens. The only time a keypress works is if it tests the condition for (char)Keys.Enter. Why is this? How can I make the form take KeyPress for keys other than enter?

Set a breakpoint on the first `if` - does execution break on any keypress? If so, investigate `e` for clues as to why your conditions aren't being met. — overslacked, Dec 27 '12 at 23:27

score 3 · Accepted Answer · edited May 23 '17 at 12:04

3

Try overriding the KeyDown method instead:

protected override void OnKeyDown(KeyEventArgs e) {
  if (e.KeyCode == Keys.Up || e.KeyCode == Keys.W) {
    picPaddle.Top -= 10;
  } else if (e.KeyCode == Keys.Down || e.KeyCode == Keys.S) {
    picPaddle.Top += 10;
  }

  base.OnKeyDown(e);
}

Also see What's the difference between KeyDown and KeyPress in .NET?

edited May 23 '17 at 12:04

Community

1
1

answered Dec 27 '12 at 23:26

LarsTech

80,625
14
153
225

@WillumMaguire In a nutshell, the up and down keys aren't characters. – LarsTech Dec 27 '12 at 23:42

score -1 · Answer 2 · answered Dec 27 '12 at 23:54

-1

the KeyPress event works when the control has the focus. The keydown event allways works . => intercept the keydown event

answered Dec 27 '12 at 23:54

Stephane Halimi

408
3
5

Per the question, the KeyPress event of the form was being used (along with the KeyPreview property being set to true). KeyDown, KeyPress and KeyUp are all available to the form in this case. – overslacked Dec 28 '12 at 00:56

KeyPress on entire form, not just one object?

2 Answers2