public ActionResult ListTrack(List <DetailTrackWithArtist> List, int?Page, string sortOrder)
        {
            int PageSize   = 10;
            int PageNumber = (Page ?? 1);

            if (List != null)
            {
                return(View(List.ToPagedList(PageNumber, PageSize)));
            }
            else
            {
                List = DetailTrackDB.ListAll();


                ViewBag.TitleSortParm     = String.IsNullOrEmpty(sortOrder) ? "TitleDesc" : "Title";
                ViewBag.FirstNameSortParm = sortOrder == "FirstName" ? "FirstNameDesc" : "FirstName";
                ViewBag.LastNameSortParm  = sortOrder == "LastName" ? "LastNameDesc" : "LastName";
                ViewBag.DateSortParm      = sortOrder == "Date" ? "DateDesc" : "Date";
                List = TrackFunctions.OrderListTrack(List, sortOrder);
                return(View(List.ToPagedList(PageNumber, PageSize)));
            }
        }