procedure TfrmMain.lbListDragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  Accept := Source = lbList;
end;

procedure TfrmMain.lbListDragDrop(Sender, Source: TObject; X, Y: Integer);
var DropPosition : Integer;
    StartPosition : Integer;
    i : Integer;
    DropPoint : TPoint;
    temp : TAudioFile;
begin
  DropPoint.X := X;
  DropPoint.Y := Y;
  with Source as TListBox do
  begin
    StartPosition := ItemAtPos(StartingPoint,True);
    DropPosition := ItemAtPos(DropPoint,True);
    temp := fFiles[startposition];
    for i := startposition downto dropposition + 1 do
    begin
      fFiles[i] := fFiles[i-1];
    end;

    for i := startposition to dropposition - 1 do
    begin
      fFiles[i] := fFiles[i+1];
    end;
    fFiles[dropposition] := temp;
    UpdateListBox;
  end;
end;