public void ChangeItemQuantity(int cartId, int itemId, int newQuantity) { var service = new Core.ShoppingCartService(_context.Instance); var cart = service.Find(cartId); var item = cart.Items.FirstOrDefault(i => i.Id == itemId); if (item != null) { _context.Database.Transactional(() => { service.ChangeItemQuantity(cart, item, newQuantity); }); } }