public string GetStudentRegistationNO(Student aStudent)
        {
            string regNo = "";
            int id;
            aStudentGateway = new StudentGateway();
            id = aStudentGateway.GetStudentRegistationNO(aStudent);
            if (id < 10)
                regNo = "000" + id;
            if (id >= 10 && id < 100)
                regNo = "00" + id;
            if (id >= 100 && id < 1000)
                regNo = "0" + id;
            if (id >= 1000)
                regNo = id.ToString();

            return regNo;
        }