How can I determine if the Backspace has been pressed in the KeyPress event?

c# winforms keypress keycode
B. Clay Shannon picture B. Clay Shannon · Apr 24, 2012 · Viewed 26.5k times · Source

This:

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.keypress.aspx

...indicates that I should have access to e.KeyCode in the KeyPress event, but I don't seem to. I'm trying to allow only 1,2,3, and backspace:

private void textBoxQH1_KeyPress(object sender, KeyPressEventArgs e) {
  if ((e.KeyChar != '1') &&
      (e.KeyChar != '2') &&
      (e.KeyChar != '3') &&
      (e.KeyChar != (Keys.Back))) {
    e.Handled = true; 
  }
}

...but "e." does not show a "KeyCode" value like the example shows, and trying KeyChar with Keys.Back scolds me with, "Operator '!=' cannot be applied to operands of type 'char' and 'System.Windows.Forms.Keys'"

So how can I accomplish this?

Answer

jorgehmv picture jorgehmv · Apr 24, 2012

try comparing e.KeyChar != (char)Keys.Back, you should cast it to char since Keys is an enumeration

see this: KeyPressEventArgs.KeyChar

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