private void mnLoaiPhong_Click(object sender, System.EventArgs e)
        {
            frmLoaiPhong f = new frmLoaiPhong();

            f.MdiParent = this;
            f.Show();
        }
 private void mnLoaiPhong_Click(object sender, System.EventArgs e)
 {
     frmLoaiPhong f = new frmLoaiPhong();
     f.MdiParent = this;
     f.Show ();
 }