Probleme beim sortieren in DBGrid

[Bummi]

Delphi-Quellcode:

Function INB(const s:String):String;
begin
   Result :=  '['  + s + ']';
end;

procedure TFRM_Main.DBG_RechnerTitleClick(Column: TColumn);
begin
  with DM_Rechner.ADO_DS_Rechner do
    if sort = INB(Column.Field.FieldName) then
      sort := INB(Column.Field.FieldName) + ' DESC'
    else
      sort := INB(Column.Field.FieldName);
end;