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("1");
lvi.SubItems.Add("2");
lvi.SubItems.Add("3");

lv.Items.Add(lvi);
}