// GET: AirFilter public async Task <ActionResult> Index(int?carID, string sortOrder) { var fuelQueryable = from s in db.Fuel.Include(a => a.Car) select s; if (carID != null && carID > 0) { fuelQueryable = fuelQueryable.Where(d => d.CarID == carID); ViewBag.CarID = carID; UpdateCarDescription(carID); } var sortDirection = ControllerHelper.GetSortOrder(sortOrder); UpdateSortDirection(sortDirection); fuelQueryable = FuelManager.AddSortToQuery(fuelQueryable, sortOrder); return(View(await fuelQueryable.ToListAsync())); }