public String GetStudentChange()
        {
            getRoleInfo();
            JObject change = teacherHelper.GetChange();

            if ((bool)change["status"])
            {
                return(change["data"].ToString(Formatting.None));
            }
            else
            {
                return(change["msg"].ToString());
            }
        }
        public String GetStudentChange()
        {
            tid = User.Identity.GetUserId();
            TeacherHelper teacherHelper = new TeacherHelper();
            JObject       change        = teacherHelper.GetChange(tid);

            if ((bool)change["status"])
            {
                return(change["data"].ToString(Formatting.None));
            }
            else
            {
                return(change["msg"].ToString());
            }
        }