private void exitAddToolStripMenuItem_Click(object sender, EventArgs e)
        {
            exitAddToolStripMenuItem.Enabled = false;
            addToolStripMenuItem.Enabled     = true;

            StudentAddForm.Hide();
            this.Height = 650;

            StudentGridView.Show();
            SearchButton.Show();
            StudentSearctBox.Show(); label10.Show();

            StudentDeleteButton.Show();
            label11.Hide();
            label12.Hide();
            FirstPageButton.Show();
            NextPageButton.Show();
            PreviousButton.Show();
            LastPageButton.Show();
        }