public ActionResult ViewScore(string classId, int classNumber)
        {
            HomeworkModel homeworkModel = new HomeworkModel();
            LessonModel   lessonModel   = new LessonModel();

            ViewBag.homeworks = homeworkModel.GetListHomeworkOfLesson(classId, classNumber);
            ViewBag.lesson    = lessonModel.GetLesson(classId, classNumber);
            return(View());
        }