private void quảnLíSinhViênToolStripMenuItem_Click(object sender, EventArgs e)
{
if (qlsv_Form == null)
{
qlsv_Form = new QuanLySinhVienForm();
qlsv_Form.FormClosed += new FormClosedEventHandler(QuanLySinhVienForm_FormClosed);
qlsv_Form.MdiParent = this;
qlsv_Form.Show();
}
}
private void QuanLySinhVienForm_FormClosed(object sender, FormClosedEventArgs e)
{
qlsv_Form = null;
}
