public CartViewModel GetCartViewModelByCustomerId(string customerId)
        {
            var  cartViewModel = new CartViewModel();
            Cart cart          = this.GetCartEntityByCustomerId(customerId);

            if (cart != null)
            {
                cartViewModel.Items = _itemService
                                      .AllViewModelsByCartIdAsync(cart.Id).ToList();
            }

            if (cartViewModel.Items != null)
            {
                foreach (var item in cartViewModel.Items)
                {
                    cartViewModel.Price += (item.Product.Price * item.ProductQuantity);
                }
            }

            return(cartViewModel);
        }