TreeView 樹形控件的加載

protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            TreeNode node = new TreeNode("風險管理政策制度庫");
            node.Value = "0";
            LoadTree(0, node);
            TreeVIEw1.Nodes.Add(node);
        }
    }

    /// <summary>
    /// 加載目錄樹
    /// </summary>
    void LoadTree(int parentId, TreeNode node)
    {
        DataSet ds = AccessHelper.Query(AccessHelper.ConnectionStringLocalTransaction,
            CommandType.Text, "select * from [dir] where [parent_id]=" + Convert.ToString(parentId),
            null);
        for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
        {
            TreeNode tn = new TreeNode(ds.Tables[0].Rows[i]["dir_name"].ToString());
            //tn.NavigateUrl = "TextList.ASPx?id=" + ds.Tables[0].Rows[i]["id"].ToString();
            //tn.Target = "mainFrame";
            tn.Value = ds.Tables[0].Rows[i]["id"].ToString();

            node.ChildNodes.Add(tn);
            LoadTree(Convert.ToInt16(ds.Tables[0].Rows[i]["id"].ToString()), tn);
        }