public IActionResult AddStudentToGroup(StudentDto studentDto) { try { var groupId = (int)TempData["groupId"]; _studentService.AddStudentToGroup(studentDto, groupId); return(RedirectToAction($"Details/{groupId}")); } catch (Exception e) { if (e is ArgumentNullException || e is ArgumentException) { ViewBag.Info = e.Message; return(View()); } return(View("Error")); } }