private

{ Private declarations }
Descending: Boolean;
SortedColumn: Integer;


procedure TForm1.ListView1ColumnClick(Sender: TObject; Column: TListColumn);
begin
TListView(Sender).SortType := stNone;
if Column.Index <> SortedColumn then
begin
SortedColumn := Column.Index;
Descending := False;
end
else
Descending := not Descending;
TListView(Sender).SortType := stText;
end;

procedure TForm1.ListView1Compare(Sender: TObject; Item1, Item2: TListItem;
Data: Integer; var Compare: Integer);
begin
if SortedColumn = 0 then Compare := CompareText(Item1.Caption, Item2.Caption)
else if SortedColumn > 0 then Compare := CompareText(Item1.SubItems[SortedColumn-1], Item2.SubItems[SortedColumn-1]);
if Descending then Compare := -Compare;
end;