public IActionResult Index(string dataTimKiem, string loaiTimKiem, int PageNumber = 1)
 {
     if (dataTimKiem == null)
     {
         var model = sanphamService.GetSanPhams();
         ViewBag.TotalPages  = Math.Ceiling(model.Count() / 1.0);
         ViewBag.dataTimKiem = dataTimKiem;
         ViewBag.loaiTimKiem = loaiTimKiem;
         var user = model.Skip((PageNumber - 1) * 1).Take(1).ToList();
         return(View(user));
     }
     else
     {
         var model = sanphamService.GetSearchSanPham(dataTimKiem, loaiTimKiem);
         ViewBag.TotalPages  = Math.Ceiling(model.Count() / 1.0);
         ViewBag.dataTimKiem = dataTimKiem;
         ViewBag.loaiTimKiem = loaiTimKiem;
         if (Math.Ceiling(model.Count() / 1.0) <= PageNumber - 1)
         {
             var user = model.Skip((1 - 1) * 1).Take(1).ToList();
             return(View(user));
         }
         else
         {
             var user = model.Skip((PageNumber - 1) * 1).Take(1).ToList();
             return(View(user));
         }
     }
 }