Why are numeric keypad numbers and regular numbers not the same in KeyEvent?

Question

This code does not allow me to enter numeric values from a numeric keypad.

private void textBox1_KeyDown( object sender, KeyEventArgs e ) {
    e.SuppressKeyPress = !( (e.KeyValue >= 48 && e.KeyValue <= 57) )
}

How can I include numerical values in general (both from regular and number keys)?

if (Key.NumPad9.Equals(e.Key) || Key.D9.Equals(e.Key)) You can use like this — madan, Oct 05 '15 at 11:45
Is there any other way to simplify it. I need only numerals and '+','-','/' and '*' in my textbox to be allowed??? — Naveen Kumar V, Oct 05 '15 at 12:00
@madan, that is really bad advice. You have taken a simple problem and proposed writing a hideous mess to solve it. Please do not recommend the use of `switch` as a solution to any question. — David Arno, Oct 05 '15 at 12:07

score 6 · Accepted Answer · answered Oct 05 '15 at 12:04

Because after all they're different keys, even though the char they represent is the same.

To get a better result you can use the Keys enum and KeyCode property:

e.SuppressKeyPress = !((e.KeyCode >= Keys.D0 && e.KeyCode <= Keys.D9) || (e.KeyCode >= Keys.NumPad0 && e.KeyCode <= Keys.NumPad9))

Or use KeyPress event because there you'll have char codes in the event args.

Inside a KeyPress event handler you can do:

 e.Handled = !Char.IsDigit(e.KeyChar)

Salah Akbari · Answer 2 · 2015-10-05T12:08:23.270

1

One solution is using the KeyPress event and TryParse method like this:

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
     int n;
     e.Handled = !int.TryParse(e.KeyChar.ToString(), out n);
}

Or you can check for NumPads like this:

e.SuppressKeyPress = !((e.KeyValue >= 48 && e.KeyValue <= 57 || (e.KeyCode >= Keys.NumPad0 && e.KeyCode <= Keys.NumPad9)));

edited Oct 05 '15 at 12:08

answered Oct 05 '15 at 12:01

Salah Akbari

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score 1 · Answer 3 · answered Oct 05 '15 at 12:03

They are not the same because they are not the same key. Keyvalue is an abstraction of the specific key you have pressed on the keyboard, not of the value that the key represents.

That said, you can simply check if either the numpad key or the other is pressed with a simple OR.

Why are numeric keypad numbers and regular numbers not the same in KeyEvent?

3 Answers3