[marcoszorrilla]

Código Delphi [-]
procedure TForm1.Button1Click(Sender: TObject);
begin
SendMessage(DateTimePicker1.Handle, WM_SYSKEYDOWN, VK_DOWN, 0);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
 DateTimePicker1.Setfocus;
keybd_event(VK_F4,0,0,0);//F4 down
keybd_event(VK_F4,0,KEYEVENTF_KEYUP,0)//F4 up
end;