public ActionResult EditSchedule(int id)
        {
            var schedule = db.getScheduleById(id);

            ViewBag.EditSchedule = schedule;
            ViewBag.time         = schedule.Start_Time.Hours + ":" + schedule.Start_Time.Minutes;
            // set dropdown model
            var classes  = db.getClassList();
            var teachers = db.getTeacherList();
            var rooms    = db.getRoomActiveList();

            var scheduleViewModel = new ScheduleViewModel
            {
                Classes           = classes,
                SelectedClassId   = schedule.Class_Id,
                ClasseEdit        = new SelectList(classes, "Class_Id", "Class_Name", schedule.Class_Id),
                Teachers          = teachers,
                SelectedTeacherId = schedule.Teacher_Id,
                Rooms             = rooms,
                SelectedRoomId    = schedule.Room_Id
            };

            return(View(scheduleViewModel));
        }