Für FMX TGrid OnTopLeftChanged nachempfinden?

[QuickAndDirty]

OK, SetTopLeft ändert ja auch ViewPortPosition.

Allerdings hat TGrid OnViewPortpositionChange nicht published... ich suche es mal

Delphi-Quellcode:

procedure TStyledGrid.SetTopLeft(const ACol, ARow: Integer);
var
  R: TRect;
  LCol, LRow: Integer;
begin
  if ((ACol >= 0) or (ARow >= 0)) and (ACol < Model.ColumnCount) and (ARow < Model.RowCount) then
  begin
    LCol := Max(0, ACol);
    LRow := Max(0, ARow);
    R := CellRect(LCol, LRow);
    AniCalculations.BeginUpdate;
    try
      if not AniCalculations.Down then
        AniCalculations.MouseDown(0, 0);
      AniCalculations.MouseLeave;
      if ACol < 0 then
        ViewportPosition := TPointF.Create(ViewportPosition.X, R.Top)
      else if ARow < 0 then
        ViewportPosition := TPointF.Create(R.Left, ViewportPosition.Y)
      else
        ViewportPosition := TPointF.Create(R.Left, R.Top);
    finally
      AniCalculations.EndUpdate;
    end;
    AniCalculations.UpdatePosImmediately(True);
  end;
end;