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);
        }
        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);
        }