Csharp: Listview convert Datatable and ListView.Group count

/// <summary>        /// 計算ListView各類子項ListViewGroup的數量        /// </summary>        /// <returns></returns>        private DataTable getNumber(ListView listview)        {            ArrayList alist = new ArrayList();            DataTable dt = new DataTable();            dt.Columns.Add("name", typeof(string));            dt.Columns.Add("number", typeof(int));            //獲取各字段名稱            for (int i = 0; i < lsvData.Columns.Count; i++)            {                alist.Add(lsvData.Columns[i].Text);            }            foreach (ListViewGroup group in listview.Groups)            {                string b = group.Header;                int c = 0;                foreach (ListViewItem itemRow in group.Items)                {                    for (int i = 0; i < itemRow.SubItems.Count; i++)                    {                        string s = itemRow.SubItems[i].Text;                        if (s == b)                        {                            c++;                        }                        //getlist = ListViewGroupConvertDatat(lsvData, group);                    }                }                getlist = ListViewGroupConvertDatat(lsvData, group);                //dt.Rows.Add(group.Header, c);                dt.Rows.Add(group.Header, getlist.Rows.Count);                group.Header = group.Header + " 共有(" + getlist.Rows.Count.ToString() + ")條記錄";                //for (int i = 0; i < alist.Count; i++)                //{                //    string s = alist[i].ToString();                //    if (s == b)                //    {                //        getlist = ListViewGroupConvertDatat(lsvData, group);                //        dt.Rows.Add(group.Header, getlist.Rows.Count);                //    }                //}            }            return dt;        }        /// <summary>        /// ListView Convert DataTabe        /// </summary>        /// <param name="lstview"></param>        /// <returns></returns>        private DataTable ListViewConvertDataTabe(ListView lstview)        {            DataTable dt = new DataTable();            //獲取各字段名稱            for (int i = 0; i < lstview.Columns.Count; i++)            {                //this.groupBox.Items.Add(lstview.Columns[i].Text);                dt.Columns.Add(lstview.Columns[i].Text, typeof(string));            }            //for (int i = 0; i < lstview.Items.Count; i++)            //{            //    dt.Rows.Add(lstview.Items[i].SubItems[0].Text, lstview.Items[i].SubItems[1].Text, lstview.Items[i].SubItems[2].Text, lstview.Items[i].SubItems[3].Text, lstview.Items[i].SubItems[4].Text);            //} //Which Subitems you want to add in the listview            //var listView1 = new ListView();            //DataTable table = new DataTable();                        foreach (ListViewItem item in lstview.Items)            {                DataRow dtRow = dt.NewRow();                int c = 0;                                foreach (ListViewItem.ListViewSubItem it in item.SubItems)                {                    dtRow[c] = it.Text;                    c++;                                   }                dt.Rows.Add(dtRow);            }            return dt;        }        /// <summary>        /// 計算ListView 中的子項集合ListViewGroup        /// </summary>        /// <param name="lstview"></param>        /// <param name="lstgroup"></param>        /// <returns></returns>        private DataTable ListViewGroupConvertDatat(ListView lstview, ListViewGroup lstgroup)        {                        DataTable dt = new DataTable();            //獲取各字段名稱            for (int i = 0; i < lstview.Columns.Count; i++)            {                //this.groupBox.Items.Add(lstview.Columns[i].Text);                dt.Columns.Add(lstview.Columns[i].Text, typeof(string));            }                        foreach (ListViewItem item in lstgroup.Items)            {                DataRow dtRow = dt.NewRow();                int c = 0;                //dt.Columns.Add(item.ToString());                //for (int i = 0; i < item.SubItems.Count; i++)                //{                //    dtRow[i] = item.SubItems[i].Text;                //}                //ListViewItem.ListViewSubItemCollection;               // ListViewItem.ListViewSubItem                ////ListViewGroupCollection                foreach (ListViewItem.ListViewSubItem it in item.SubItems)                                {                    dtRow[c] = it.Text;                      c++;                }                dt.Rows.Add(dtRow);            }                   return dt;        }