Winform TreeList递归绑定树节点

/// <summary>
/// 绑定树目录
/// </summary>
/// <param name="parentId">父ID</param>
/// <param name="node">父节点</param>
private void BindTree(int parentId, TreeListNode parentNode)
{
    StringBuilder sb = new StringBuilder();
    sb.Append("select * from tbTree order by [Index]");
    DataSet ds = DbHelperSQL.QueryDataSet(sb.ToString());           
    DataRow[] rows = ds.Tables[0].Select("ParentID=" + parentId);
    foreach (DataRow row in rows)
    {
        TreeListNode treeNode;
        //添加根节点
        if (parentNode == null)
        {
            treeNode = this.treeList1.AppendNode(new object[] { row["ConText"] }, null);
        }
        else
        {
            treeNode = parentNode.TreeList.AppendNode(new object[] { row["ConText"] }, parentNode);
        }
        BindTree(Convert.ToInt32(row["ID"]), treeNode);
        treeNode.ExpandAll();
    }
}