public void PopulateExamDetails()
        {
            var dt = new DataTable();

            dt.Columns.Add("SN");
            dt.Columns.Add("NAME");
            dt.Columns.Add("SCHOOL");
            dt.Columns.Add("EXAMINATION");
            dt.Columns.Add("FEES");
            dt.Columns.Add("EXAMID");


            var Exams = DropDownManager.GetRegisteredStudents();
            int sn    = 0;

            foreach (var item in Exams)
            {
                string id         = item.StudentID.ToString();
                string Name       = item.StudentName;
                string schoolName = item.SchoolName;
                string Exam       = item.ExamCode;
                string ExamId     = item.ExamId.ToString() + "," + item.StudentID.ToString() + "," + item.SchoolId.ToString();
                string Fee        = item.Fee;
                sn++;
                dt.Rows.Add(sn, Name, schoolName, Exam, Fee, ExamId);
            }
            gvSubject.DataSource = dt;
            gvSubject.DataBind();
        }