private void button1_Click(object sender, EventArgs e)
        {
            addSessionControl edit_ses = new addSessionControl();

            edit_ses.updateSession(int.Parse(lec_1.Text), int.Parse(lec_2.Text), int.Parse(lec1_tag.Text), int.Parse(group.Text), int.Parse(subject.Text), int.Parse(no_of_student.Text), decimal.Parse(duration.Text), int.Parse(sessionId.Text));
            subjectView.DataSource = review.GetSessionDetails();
            reset();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            addSessionControl delete = new addSessionControl();

            delete.deleteRow(int.Parse(sessionId.Text));
            reset();
            subjectView.DataSource = review.GetSessionDetails();
        }