private void btPhong_Click(object sender, EventArgs e)
 {
     Phong p = new Phong();
     p.ShowDialog();
     pCtrl.HienThiComboBox(cmbMaPhong);
 }
 private void btPhong_Click(object sender, EventArgs e)
 {
     Phong p = new Phong();
     p.ShowDialog();
     UpdateListPhong();
 }