public async Task <IActionResult> AddTeacherToSubject(int subjectId, int teacherId = -1) { if (_subjectService.DoesSubjectBelongsToTeacher(subjectId, teacherId)) { return(RedirectToAction("IndexTeacher", new { subjectId = subjectId })); } if (teacherId != -1) { // studentId checking Console.WriteLine(" idddd Teacher = " + teacherId); await _subjectService.AddTeacherToSubject(subjectId, teacherId); } Teacher teacher = await _authentication.GetCurrentTeacherAsync(); if (!_subjectService.DoesSubjectBelongsToTeacher(subjectId, teacher.Id)) { return(RedirectToAction("IndexTeacher", new { subjectId = subjectId })); } Subject subject = _databaseWorker.GetSubjectById(subjectId); IEnumerable <Teacher> availableTeachers = await _subjectService.GetTeachersWithoutThisSubject(subject); TeacherSubjectViewModel model = new TeacherSubjectViewModel { Subject = subject, Teachers = availableTeachers }; return(View(model)); }