C# winfrom listview 多窗口调用

Form1

        private void button1_Click(object sender, EventArgs e)
        {
            Form f = new Form2(ref listView1);
            f.Activate();
            f.Show();
        }

Form2

        private ListView lv;
        public Form2(ref ListView _lv)
        {
            this.lv = _lv;
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            ListViewItem lvi = new ListViewItem();

            lvi.SubItems.Add("");
            lvi.SubItems.Add("");
            lvi.SubItems.Add("");

            lv.Items.Add(lvi);
        }