private void ChangePassword(HttpContext context)
        {
            int    U_ID        = Convert.ToInt32(context.Request["U_ID"]);
            string oldPassword = context.Request["oldPassword"];
            string NewPassword = context.Request["NewPassword"];

            BLL.UserInfo bll = new BLL.UserInfo();
            context.Response.Write(bll.ChangePassword(U_ID, oldPassword, NewPassword));
        }