private void tạoHộiĐồngMớiToolStripMenuItem_Click(object sender, EventArgs e)
{
TaoHoiDong f = new TaoHoiDong();
f.MdiParent = this;
f.Show();
}
private void btnThem_Click(object sender, EventArgs e)
{
TaoHoiDong f = new TaoHoiDong();
f.MdiParent = this.MdiParent;
f.Show();
}