[NumLock]

Код:

var
  Columns: Integer;
  ColumnsWidth: Integer;
  ScrollInfo: TScrollInfo;
begin
  ColumnsWidth:=0;
  for Columns:=0 to DBGrid1.Columns.Count-1 do Inc(ColumnsWidth, DBGrid1.Columns[Columns].Width);
  ScrollInfo.cbSize:=SizeOf(TScrollInfo);
  ScrollInfo.fMask:=SIF_ALL;
  GetScrollInfo(DBGrid1.Handle, SB_HORZ, ScrollInfo);
  ScrollInfo.nPage:=MulDiv(ScrollInfo.nMax-ScrollInfo.nMin, DBGrid1.Width, ColumnsWidth);
  SetScrollInfo(DBGrid1.Handle, SB_HORZ, ScrollInfo, True);
end;