private void AddChildB_Click(object sender, EventArgs e) { ListViewItem li = new ListViewItem(MainLV.Groups[1]); li.Text = string.Format("Item{0}", _itemsCount.ToString()); _itemsCount++; if (_tlvdm != null) { //MessageBox.Show(_tlvdm.SubItems.Count.ToString()); Classes.BaseListViewItem _stlvdm = new Classes.BaseListViewItem(); _stlvdm.Caption = li.Text; _tlvdm.SubItems.Add(_stlvdm); li.Tag = _stlvdm; } MainLV.Items.Add(li); }