(C++ Builder) How do I let a TForm be dragged?

void __fastcall TForm1::FormMouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
   if( Shift.Contains( ssLeft ) )
   {
       ReleaseCapture();
       SendMessage(Handle,WM_NCLBUTTONDOWN,2,0);
   }
}