Tschenrechner -> Buttons

[p0w3r5tr34m3r]

ich würde es so machen

Delphi-Quellcode:

var comma: boolean; // globale variable
{...}
procedure TForm1.CommaClick(Sender: TObject); 
begin
  if comma then
    exit
  else begin
    edit1.text := edit1.text + ',';
    comma := true;
  end;
end;