Capturing a 'delete' key press

I can't figure out how to capture the De开发者_如何学运维letekey press. I found out that in ASCII code table, it is at 127 place, but if (Key = #127) then got me nowhere.

Then I checked the value of VK_DELETE which was 47. Tried to use that, but it didn't work.

The KeyPreview := true is set in my form.

I tried to add the ShowMessage(IntToStr(Ord(Key))) to the Forms KeyPress event, but I never got the message popup while clicking the Delete key.

I need to handle the Delete key press in dynamicaly created Edit fields. I want to control what part of the text user can erase in that field, and I know how to handle the text deletion using Backspace key, now need to figure out how to do it with Delete key.

Thanks

You should handle the OnKeyDown instead of the OnKeyPress event. If you do that then VK_DELETE should work for you. Note that the parameter for OnKeyDown and OnKeyUp is a Word, not a Char as for OnKeyPress.

Mghie has the correct answer, here is a sample:

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
   if Key=VK_DELETE then
     showmessage('Delete key was pressed');
end;

Note that the user can also delete text using cut-to-clipboard so you may need to handle that as well.

You can use OnKeyDown event to filter the undesired Delete key pressed:

procedure TForm1.Edit1KeyDown(Sender: TObject; var Key: Word; Shift:
    TShiftState);
begin
  if Key = VK_DELETE then begin
    Beep;
    Key:= 0;
  end;
end;