public ActionResult New()
        {
            ModifyCustomerViewModel model = new ModifyCustomerViewModel
            {
                MembershipTypes = _context.MembershipTypes.ToList()
            };

            return(View("ModifyCustomer", model));
        }
        public ActionResult Edit(int id)
        {
            ModifyCustomerViewModel model = new ModifyCustomerViewModel
            {
                Customer        = _context.Customers.SingleOrDefault(c => c.Id == id),
                MembershipTypes = _context.MembershipTypes.ToList()
            };

            return(View("ModifyCustomer", model));
        }
        public ActionResult Save(ModifyCustomerViewModel model)
        {
            if (!ModelState.IsValid)
            {
                ModifyCustomerViewModel modifyCustomerViewModel = new ModifyCustomerViewModel
                {
                    Customer        = model.Customer,
                    MembershipTypes = _context.MembershipTypes.ToList()
                };
                return(View("ModifyCustomer", modifyCustomerViewModel));
            }
            if (model.Customer.Id.Equals(0))
            {
                byte discountRate = 0;
                if (model.Customer.MembershipTypeId.Equals(1))
                {
                    discountRate = 0;
                }
                if (model.Customer.MembershipTypeId.Equals(2))
                {
                    discountRate = 10;
                }
                if (model.Customer.MembershipTypeId.Equals(3))
                {
                    discountRate = 15;
                }
                if (model.Customer.MembershipTypeId.Equals(4))
                {
                    discountRate = 20;
                }

                model.Customer.DiscountRate = discountRate;
                _context.Customers.Add(model.Customer);
            }
            else
            {
                var customer = _context.Customers.SingleOrDefault(c => c.Id == model.Customer.Id);
                customer.MembershipTypeId = model.Customer.MembershipTypeId;
                customer.Birthday         = model.Customer.Birthday;
                customer.Name             = model.Customer.Name;
            }
            _context.SaveChanges();
            return(RedirectToAction("Index", "Customer"));
        }