Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

{ 
  There's no possibility to automatically 
  open a TDateTimePicker than to send a F4 to it.}

 { 
  Es gibt't keine Moglichkeit, einen TDateTimePicker automatisch zu offnen, 
  als F4 ihm zu senden 
}


 procedure TForm1.Button1Click(Sender: TObject);
 begin
   DateTimePicker1.Perform(WM_KEYDOWN, VK_F4, 0);
   DateTimePicker1.Perform(WM_KEYUP, VK_F4, 0);
 end;