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);
        }