private
    { Private declarations }
    SortCol: Integer;
    SortWay: Integer;

procedure TMainFrm.ListView1ColumnClick(Sender: TObject; Column: TListColumn);
begin
  SortCol:=Column.Index;
  if (SortWay=1) then SortWay:=-1 else SortWay:=1;
  (Sender as TCustomListView).AlphaSort;
end;

procedure TMainFrm.ListView1Compare(Sender: TObject; Item1, Item2: TListItem; Data: Integer; var Compare: Integer);
var
  t: Integer;
begin
  if (SortCol=0) then
  begin
    Compare:=SortWay * CompareText(Item1.Caption,Item2.Caption);
  end else
  begin
    t:=SortCol-1;
    Compare:=SortWay * CompareText(Item1.SubItems[t],Item2.SubItems[t]);
  end;
end;