private async void button_Click_2(object sender, RoutedEventArgs e)
        {
            DataClassesLinqDataContext db = new DataClassesLinqDataContext
                                                (DataAccessClassLinq.connectionStringLinq);

            StudentIntImplementation          a = new StudentIntImplementation();
            AdmissionStudentIntImplementation b = new AdmissionStudentIntImplementation();

            DAL.Student           st          = a.getStudent(id.Text);
            DAL.Admission_Student admissionSt = null;

            try
            {
                admissionSt = db.Admission_Students.FirstOrDefault(ee => ee.Admission_Student_ID.Equals(st.Admissin_Student_ID));
            }
            catch
            {
                //do nothing
            }


            if (st == null)
            {
                await this.ShowMessageAsync("Error", "Student not found.");
            }
            else
            {
                DAL.Student_Regular_Fee stReg = db.Student_Regular_Fees.FirstOrDefault(ee => ee.Student_ID.Equals(st.Student_ID));

                fullName.Text = admissionSt.Full_Name;
                grade.Text    = admissionSt.Interested_Grade;
                group.Text    = admissionSt.Group;

                /*if (stReg == null)
                 *  mo.Text = "";
                 * else
                 *  mark.Text = stResult.Viva_Exam_Mark;*/
            }
        }