public ActionResult Create(AppointmentBindingModel model)
        {
            if (!ModelState.IsValid)
            {
                return(View());
            }

            string userId      = User.Identity.GetUserId();
            var    appointment = new Appointment()
            {
                StartDateTime = model.StartDateTime,
                EndDateTime   = model.EndDateTime,
                UserId        = userId
            };

            if (service.Create(appointment, userId))
            {
                return(RedirectToAction("Index"));
            }
            else
            {
                int allowedAppointments = int.Parse(System.IO.File.ReadAllText(HostingEnvironment.MapPath("~/") + "applicationSettings.txt"));

                ModelState.AddModelError("", "There are already " + allowedAppointments + " parallel appointments");

                return(View());
            }
        }
        public ActionResult Edit(AppointmentBindingModel model, int id)
        {
            if (!ModelState.IsValid)
            {
                ViewBag.Id = id;

                return(View());
            }

            var appointment = service.Get(id);

            appointment.StartDateTime = model.StartDateTime;
            appointment.EndDateTime   = model.EndDateTime;
            service.Update(appointment);

            return(RedirectToAction("Index"));
        }