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Handling key presses on a TEdit

Posted on 2008-10-25
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Last Modified: 2013-11-23
Hi all,

Just a question I can't figure out.

I've got a TEdit which must handle the - and + of the numeric keypad, but not the - and + of the alphanumeri part of the keyboard.
When I put a break point on the OnKeyDown event I see that it makes a difference on the numeric and alphanumeric part of the - sign (#189 and #109).

But how can I code that when the subtract key is pressed on the numeric keypad that it will not put the - in the TEdit box and will do when the alphanumeric - is pressed?

Thanks in advance,

JeePeeTee
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Question by:JeePeeTee
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5 Comments
 
LVL 28

Accepted Solution

by:
2266180 earned 250 total points
ID: 22802915
something like this?
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
 
type
  TForm1 = class(TForm)
    Edit1: TEdit;
    procedure Edit1KeyPress(Sender: TObject; var Key: Char);
    procedure Edit1KeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
  private
    { Private declarations }
    pressed:word;
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
  if (key='-') and (pressed=109) then
    key:=#0;
end;
 
procedure TForm1.Edit1KeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  pressed:=key;
end;
 
end.

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LVL 4

Author Comment

by:JeePeeTee
ID: 22803034
Thanks,

Kinda weird that you can't do it without declaring a pricate symbol.
But ah, well, it works!

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LVL 4

Author Closing Comment

by:JeePeeTee
ID: 31509932
It works, though it's weird that it must be done with a private symbol.
0
 
LVL 28

Expert Comment

by:2266180
ID: 22803073
Why a B grade? see grading tips here: http://www.experts-exchange.com/help.jsp#hi403
0
 
LVL 4

Author Comment

by:JeePeeTee
ID: 22812682
It's a B-grade because the solution is good, but not excellent. Like I mentioned, the solution works, but I think it's kinda weird that I need a private symbol to pass trhough two seprate OnKey events.
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