vs2005动态构建树型结构

private void Page_Load(object sender, System.EventArgs e)
         {
            // 定义数据库连接
            SqlConnection CN = new SqlConnection();
            try
            {
               //初始化连接字符串
               CN.ConnectionString= "data source=pmserver;
               initial catalog=Benchmark;
               persist security info=False;
               user id=sa;
               Password=sa;";
               CN.Open();
               SqlDataAdapter adp = new SqlDataAdapter("select * from tbTree",CN);
               DataSet ds=new DataSet();
               adp.Fill(ds);
               this.ViewState["ds"]=ds;
            }
            catch (Exception ex)
            {
               Session["Error"] = ex.ToString();
               Response.Redirect("error.aspx"); //̀跳转程序的公共错误处理页面
            }
            finally
            {
               CN.Close();
            }
            //调用递归函数，完成树形结构的生成
            AddTree(0, (TreeNode)null);
         }
      //递归添加树的节点
         public void AddTree(int ParentID,TreeNode pNode)
         {
            DataSet ds=(DataSet) this.ViewState["ds"];
            DataView dvTree = new DataView(ds.Tables[0]);
            //过滤ParentID,得到当前的所有子节点
            dvTree.RowFilter = "[PARENTID] = " + ParentID;
            foreach(DataRowView Row in dvTree)
            {
               TreeNode Node=new TreeNode() ;
               if(pNode == null)
               {
                  //添加根节点
                  Node.Text = Row["ConText"].ToString();
                  TreeView1.Nodes.Add(Node);
                  Node.Expanded=true;
                  AddTree(Int32.Parse(Row["ID"].ToString()), Node);
                 //再次递归
                }
              else
              {
                  //̀添加当前节点的子节点
                  Node.Text = Row["ConText"].ToString();
                  pNode.Nodes.Add(Node);
                  Node.Expanded = true;
                  AddTree(Int32.Parse(Row["ID"].ToString()),Node);
                  //再次递归
               }
            }