public async Task <ActionResult> GetProductList(string sortOrder)
{
ViewBag.SortPrice = String.IsNullOrEmpty(sortOrder) ? "price_desc" : "";
ViewBag.SortAmount = String.IsNullOrEmpty(sortOrder) ? "amount_desc" : "";
var product = _mapper.Map <List <ProductViewModel> >
(await _sortService.SortProductPrice(sortOrder));
ViewBag.Categories = _mapper.Map <List <CategoryViewModel> >(
(await _categoryService.GetCategories()).ToList());
return(View(product));
}