好久一段時間無上blog了, 最近在看treeview的資料, 用遞歸的方法處理sql數據庫中數據並手動加至treeview還是有點問題未太明白

以下是一段遞歸的代碼, 功能是用代碼實現treeview的實現, 不過未加入sql庫的數據實現
    protected void Page_Load(object sender, EventArgs e)
    {
        this.TreeView1.Nodes.Clear();  //先清除treeview所有的節點
        maketree();     //產生treeview
        TreeView1.DataBind();   //數據綁定
    }

    protected void maketree()
    {
        TreeNode RootNode;    //定義一個節點對像
        for (int i = 0; i < 10;i++ )    //首先產生10個根節點
        {
            RootNode = new TreeNode();    //實例代一個節點對像;
            RootNode.Text = "根節點" + i.ToString();    //設定節點顯示文件信息
            RootNode.Value = i.ToString();       //設定節點值
            this.TreeView1.Nodes.Add(RootNode);     //將節點加到TreeView控件
            MakeChildNode(RootNode, i);      //一個遞歸函數, 產生根節點的子節點
        }
    }

    protected void MakeChildNode(TreeNode tn, int ParentID)
    {
        TreeNode CHildNode;
        for (int i = 0; i < ParentID; i++)
        {
            CHildNode = new TreeNode("子節點" + i.ToString(), i.ToString());
            tn.ChildNodes.Add(CHildNode);
            //MakeChildNode(CHildNode,i);    //這里沒有遞歸下去, 由于只是手動實現了一下treeview的代碼, 在使用遞前需先判斷一下當節點是否有下級婁據,或控制一下遞歸的層次數量
        }
    }


以下是一段有問題的代碼, 無法運行成功, 問題到底在哪?鬱悶........
    protected void TV_binder()
    { 
            SqlConnection conn = DB.createConection();
            SqlCommand cmd = new SqlCommand("select * from Dep",conn);
            SqlDataAdapter adp = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            adp.Fill(ds, "Dep");
            cmd.CommandText = "select * from Class";
            adp = new SqlDataAdapter(cmd);
            adp.Fill(ds,"Class");

            if (ds.Tables["Dep"].Rows.Count > 0)
            {
                for (int i = 0; i < ds.Tables["Dep"].Rows.Count; i++)
                {//根據sql庫插入樹節點
                    TreeNode tn = new TreeNode();
                    tn.Text = ds.Tables["Dep"].Rows[i]["DepthName"].ToString();
                    tn.NavigateUrl = "NavMenu.aspx?act=list&Dep=" + ds.Tables["Dep"].Rows[i]["DepID"].ToString();
                    this.tv_leftmenu.Nodes.Add(tn);
                    TV_ChildTreeNode(Convert.ToInt32(ds.Tables["Dep"].Rows[i]["DepID"].ToString()),tn,ds.Tables["Class"]);
                }
            }
            this.tv_treeview.DataBind();
        }

    protected void TV_ChildTreeNode(int DepID,TreeNode tn,DataTable dt)
    {
        dt.DefaultView.RowFilter= "DepID";
        DataView dv = dt.DefaultView;
        adp.Fill(ds);
        if (dv.Count > 0)
        {
            for (DataRowView drv in dv)
            {//根據sql庫插入樹節點
                TreeNode Child_tn = new TreeNode();
                Child_tn.Text = drv["ClassName"].ToString();
                Child_tn.NavigateUrl = "NavMenu.aspx?act=list&Dep=" + drv["DepID"].ToString();
                tn.ChildNodes.Add(Child_tn);
                TV_ChildTreeNode(Convert.ToInt32(drv["DepID"].ToString()), Child_tn,dt);
            }
        }
    }