public ActionResult Login(DefaultControllerLoginVM model)
 {
     if (!ModelState.IsValid)
     {
         return View(model);
     }
     else
     {
         TryUpdateModel(model);
         AuthenticationManager.Authenticate(model.UserName, model.Password, model.UserType);
         if (AuthenticationManager.LoggedUser == null)
         {
             return RedirectToAction("Login", "Default");
         }
         if (ObjectContext.GetObjectType(AuthenticationManager.LoggedUser.GetType()).Equals(typeof(Administrator)))
         {
             return RedirectToAction("Home", "Admin");
         }
         if (ObjectContext.GetObjectType(AuthenticationManager.LoggedUser.GetType()).Equals(typeof(Teacher)))
         {
             return RedirectToAction("Index", "Teacher");
         }
         if (ObjectContext.GetObjectType(AuthenticationManager.LoggedUser.GetType()).Equals(typeof(Student)))
         {
             return RedirectToAction("Index", "Student");
         }
         return RedirectToAction("Login", "Default");
     }
 }
 public ActionResult Login()
 {
     DefaultControllerLoginVM model = new DefaultControllerLoginVM();
     Administrator admin = new Administrator();
     return View(model);
 }