public ActionResult Registration(RegProducerViewModel model)
        {
            if (!ModelState.IsValid)
            {
                ViewBagProducerList();
                return(View("Index", model));
            }

            ViewBagAppointmentList(model.ProducerId);
            var producerName = DB.producernames.Single(x => x.ProducerId == model.ProducerId).ProducerName;
            var company      = DB.AccountCompany.SingleOrDefault(x => x.ProducerId == model.ProducerId);

            // если от данного производителя регистрировались, возвращаем форму для регистрации пользователя с моделью RegDomainViewModel
            if (company != null)
            {
                var modelDomainView = new RegDomainViewModel()
                {
                    Producers = model.ProducerId, ProducerName = producerName
                };
                ViewBag.DomainList = company.CompanyDomainName
                                     .Select(x => new OptionElement {
                    Text = '@' + x.Name, Value = x.Id.ToString()
                })
                                     .ToList();
                return(View("DomainRegistration", modelDomainView));
            }

            var modelUi = new RegViewModel()
            {
                ProducerId = model.ProducerId, ProducerName = producerName
            };

            return(View(modelUi));
        }
        /// <summary>
        /// Возвращает форму выбора производителя
        /// </summary>
        /// <returns></returns>
        public ActionResult Index()
        {
            var model = new RegProducerViewModel();

            ViewBagProducerList();
            return(View(model));
        }