public IActionResult FilterAndSearch(string search, string ploai, string mahang, string filter, int?pagenumber)
        {
            float minprice = float.Parse(filter.Substring(filter.IndexOf('đ') + 1, filter.IndexOf(' ') - 1));
            float maxprice = float.Parse(filter.Substring(filter.LastIndexOf('đ') + 1));

            pageNumber = pagenumber ?? 1;
            SanPhamBUS     sanphambus = new SanPhamBUS();
            List <SanPham> list       = sanphambus.FilterAndSearch(minprice, maxprice, search, ploai, mahang, pageSize, pageNumber);
            List <SanPham> tong       = sanphambus.FilterAndSearch(minprice, maxprice, search, ploai, mahang);

            ViewBag.TrangHienTai = pageNumber;
            ViewBag.TongTrang    = TongTrang(tong);
            ViewBag.TrangThai    = "filterandsearch";
            ViewBag.Filter       = filter;
            ViewBag.Search       = search;
            if (ploai != null)
            {
                ViewBag.PhanLoai = ploai == "Nam" ? "Nam" : "Nu";
            }
            ViewBag.ThuongHieu = mahang;
            if (ploai != null && ploai != "")
            {
                ViewBag.Loai = ploai == "Nam" ? "Nam" : "Nu";
            }
            else
            {
                ViewBag.PhanLoai = ploai;
            }
            List <HangSanPham> hang = ctx.HangSanPham.ToList();

            ViewBag.Hang = hang;
            return(View("List", list));
        }