public SectionAddModify(SectionMainform sMain)
 {
     InitializeComponent();
     cgrade     = new ClassGrade();
     section    = new ClassSection();
     this.sMain = sMain;
 }
        private void toolStripButton4_Click(object sender, EventArgs e)
        {
            SectionMainform frm = new SectionMainform();

            frm.ShowDialog();
        }