public async Task <ActionResult> Index(int categoryId, int?page) { DBModelContainer db = new DBModelContainer(); ProductionService service = new ProductionService(); // get all products of a given category List <Production> prs = await service.getProductsByCategoryId(categoryId); if (prs != null && prs.Count > 0) { int pageSize = 16; int pageNumber = (page ?? 1); return(View(prs.ToPagedList(pageNumber, pageSize))); } return(RedirectToAction("Index", "Category")); }