public ActionResult Add()
        {
            var classDto = new CourseDto
            {
                Lessons    = new SelectList(lessonService.GetAll(), "Id", "Name"),
                Teachers   = new SelectList(teacherService.GetTeachers(), "Id", "TeacherCode"),
                Classrooms = new SelectList(classroomService.GetClassrooms(), "Id", "Name")
            };

            return(View(classDto));
        }
 public IActionResult GetClassrooms()
 {
     try
     {
         return(Ok(_classroomService.GetClassrooms()));
     }
     catch (Exception ex)
     {
         return(BadRequest(ex.Message));
     }
 }