public void InsertOrUpdate(Calendar calendar)
 {
     if (calendar.CalendarId == default(int)) {
         // New entity
         context.Calendars.Add(calendar);
     } else {
         // Existing entity
         context.Entry(calendar).State = EntityState.Modified;
     }
 }
 public ActionResult Create(Calendar calendar)
 {
     if (ModelState.IsValid) {
         calendarRepository.InsertOrUpdate(calendar);
         calendarRepository.Save();
         return RedirectToAction("Index");
     } else {
         return View();
     }
 }