递归生成树Treeview

 SqlConnection Conn = new SqlConnection("server=.;database=Test;uid=sa;pwd=sa");
        DataSet ds;
        protected void Page_Load(object sender, EventArgs e)
        {
            Conn.Open();
            this.createDataSet();
            Conn.Close();
            this.InitTree(tvMenu.Nodes, "0");
        }
        private DataSet createDataSet()//返回数据库表
        {
            ds = new DataSet();
            string sqlStr = "select * from Tree ";
            SqlDataAdapter cmdSelect = new SqlDataAdapter(sqlStr, Conn);
            cmdSelect.Fill(ds, "Tree");
            return ds;
        }
        protected void InitTree(TreeNodeCollection Nds, string parentId)//用递归方法动态生成节点
        {
            DataView dv = new DataView();
            TreeNode tmpNode;
            dv.Table = ds.Tables["Tree"];
            dv.RowFilter = "ParentId=" + "'" + parentId + "'";
            foreach (DataRowView drv in dv)
            {
                tmpNode = new TreeNode();
                tmpNode.Value = drv["Id"].ToString();
                tmpNode.Text = drv["Name"].ToString();
                if (drv["ParentId"].ToString() == "0")
                {
                    tmpNode.SelectAction = TreeNodeSelectAction.None;
                }
                else
                {
                    tmpNode.NavigateUrl = drv["Url"].ToString();//设置超链接
                }
                tmpNode.ExpandAll();//展开所有子节点
                Nds.Add(tmpNode);
                this.InitTree(tmpNode.ChildNodes, tmpNode.Value);
            }
        }