public ActionResult StudentSignIn(FormCollection form)
        {
            try {
                int scheduleId = (int)TempData["class"];
                TempData["class"] = db.getScheduleById(scheduleId);
                List <Yoga_User> yu = db.getScheduleSignUpList(scheduleId).ToList();

                foreach (Yoga_User user in yu)
                {
                    String attendance = form[user.U_Id.ToString()];
                    db.changeClass_LogStatus(user.U_Id, scheduleId, attendance);
                }
                return(View(yu.OrderBy(x => x.U_Last_Name).ToList().OrderBy(x => x.U_First_Name).ToList()));
            }
            catch (Exception ex)
            {
                string error = ex.ToString();
                Response.Write(error);
                EmailSender.sendEmail(error);
                Console.WriteLine(error);

                return(View());
            }
        }