TForm.ActiveControl Property

Specifies the control that has focus on the form.

Pascal

property ActiveControl: TWinControl;

C++

__property TWinControl * ActiveControl;

Description

Use ActiveControl to get or set the control that has focus on the form. Only one control can have focus at a given time in an application.

If the form does not have focus, ActiveControl is the control on the form that will receive focus when the form receives focus.

Note: When focus shifts to another control, ActiveControl is updated before the OnExit event occurs.

C++ Examples:

Copy Code

/*
Place a TTimer object in the form and enter Timer1Timer in 
the OnTimer event.  Place other controls in the form and 
change the active control at runtime.  The following event 
handler responds to timer events by moving the active control
one pixel to the right every 100 miliseconds:
*/
void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
  Timer1->Interval = 100;
  if (ActiveControl)
    ActiveControl->Left = ActiveControl->Left + 1;
}

Delphi Examples:

Copy Code

{
Place a TTimer object in the form and enter Timer1Timer in 
the OnTimer event.  Place other controls in the form and 
change the active control at runtime.  The following event 
handler responds to timer events by moving the active control
one pixel to the right every 100 miliseconds:
} 
procedure TForm1.Timer1Timer(Sender: TObject);
begin
  Timer1.Interval := 100;
  if ActiveControl <> nil then
    ActiveControl.Left := ActiveControl.Left + 1;
end;