public ActionResult EditExams([Bind(Include = "StudentGroup,Exams")] StudentGroupEditExamsViewModel viewModel) { if (viewModel == null) { return(new HttpStatusCodeResult(HttpStatusCode.BadRequest)); } var studentGroupID = viewModel.StudentGroup?.Id; if (studentGroupID != null) { var studentGroup = _studentGroupService.GetByID((int)studentGroupID); foreach (var examViewModel in viewModel.Exams) { var exam = _examCoreService.GetByID(examViewModel.Id); if (examViewModel.IsAssociatedToStudentGroup == true) { _examCoreStudentGroupService.AssociateExamToStudentGroup(exam, studentGroup); } else if (examViewModel.IsAssociatedToStudentGroup == false) { _examCoreStudentGroupService.DisassociateExamFromStudentGroup(exam, studentGroup); } } } return(RedirectToAction("Details", new { id = studentGroupID })); }