delphi ListBox控件拖放Item位置

procedure TForm1.ListBox1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
  var
  Idx: Integer;
  Pos: TPoint;
begin
  Accept := False;
  if Sender is TListBox then
  with Sender as TListBox do
  begin
    Pos.X := X;
    Pos.y := Y;
    Idx := ItemAtPos(Pos, True);
    if (Idx > -1) and (idx <> ItemIndex) then
      Accept := True;
  end;
end;

procedure TForm1.ListBox1DragDrop(Sender, Source: TObject; X, Y: Integer);
var
  Idx: Integer;
  Pos: TPoint;
begin
  if Sender is TListBox then
  begin
    with Sender as TListBox do
    begin
      Pos.X := X;
      Pos.y := Y;
      Idx := ItemAtPos(Pos, True);
      Items.Move(ItemIndex, Idx);
      ItemIndex := Idx;
    end;
  end;
end;