public ActionResult AddCustomer(Customer customer)
        {
            if (!ModelState.IsValid)
            {
                var errors = ModelState.Values.SelectMany(v => v.Errors);
                //var customer = _Context.Customers.SingleOrDefault(c => c.Id == viewmodel.Customers.Id);

                var viewmodel1 = new ViewModel_CustomersMembershipType()
                {
                    Customer        = customer,
                    MembershipTypes = _Context.MembershipTypes.ToList()
                };
                return(View("CreateCustomer", viewmodel1));
            }
            else
            {
                if (customer.Id != null)
                {
                    var customers = _Context.Customers.SingleOrDefault(c => c.Id == customer.Id);
                    customers.Name        = customer.Name;
                    customers.DateOfBirth = customer.DateOfBirth;
                    customers.IsSubscribedToNewsLetter = customer.IsSubscribedToNewsLetter;
                    customers.MembershipTypeId         = customer.MembershipTypeId;
                }
                else
                {
                    _Context.Customers.Add(customer);
                }
                _Context.SaveChanges();
                return(RedirectToAction("Index", "Customers"));
            }
        }
        public ActionResult CreateCustomer()
        {
            var viewmodel = new ViewModel_CustomersMembershipType()
            { //Customer =new Customer(),
                MembershipTypes = _Context.MembershipTypes.ToList()
            };

            return(View(viewmodel));
        }
        public ActionResult Edit(int id)
        {
            var viewmodel = new ViewModel_CustomersMembershipType()
            {
                Customer        = _Context.Customers.SingleOrDefault(c => c.Id == id),
                MembershipTypes = _Context.MembershipTypes.ToList()
            };

            return(View("CreateCustomer", viewmodel));
        }