procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
    if key in ['.']  then
  begin
    application.MessageBox('¸ÃÏî±ØÐëΪÕûÊý£¬Çë¸üÕý£¡','¾¯¸æ',mb_ok+mb_iconinformation);
    edit1.SetFocus;
    edit1.Clear;
    exit;
  end;
end;