C# 里TreeView绑定数据库实现分类

codes=c#]
//从数据库中读取数据
            SqlConnection con = new SqlConnection("server=127.0.0.1\\sqlexpress;uid=sa;");
            con.Open();
            con.ChangeDatabase("STggggg");
            SqlCommand cmd = new SqlCommand("select * from 产品树 where NodeType='f'", con);
            //cmd.CommandType = CommandType.StoredProcedure;
            SqlDataAdapter sda = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            try
            {
                sda.Fill(ds);
            }
            catch
            {
            }
            finally
            {
                cmd = null;
                con.Close();
            }
            //往TreeView中添加树节点
            //添加根节点
            TreeNode tn = new TreeNode();
            tn.Text = "所有产品";
            tn.Name = "0";//Name作为ID
            tn.Tag = "0";//Tag作为RootID
            tn.ImageIndex = 0;
            tn.SelectedImageIndex = 0;
            tv.Nodes.Add(tn);//该TreeView命名为tv
            tv.SelectedNode = tv.TopNode;
            //把其他节点加上去
            if (ds != null)
            {[/codes][codes=c#]
                foreach (DataRow dr in ds.Tables[0].Rows)
                {
                    tn = new TreeNode();
                    tn.Text = dr["Product"].ToString();
                    tn.Name = dr["CateID"].ToString();//Name作为CateID
                    tn.Tag = dr["RootID"].ToString();//Tag作为RootID
                    tn.ImageIndex = 1;
                    tn.SelectedImageIndex = 1;
                    //判断是否为主节点
                    if (dr["CateID"].ToString() == dr["RootID"].ToString())
                    {
                        //主节点
                        tv.SelectedNode = tv.TopNode;
                    }
                    else
                    {
                        //其他节点
                        if (tv.SelectedNode.Name != dr["ParentID"].ToString())
                        {
                            TreeNode[] tn_temp = tv.Nodes.Find(dr["ParentID"].ToString(), true); //通过ParentID查找父节点
                            if (tn_temp.Length > 0)
                            {
                                tv.SelectedNode = tn_temp[0]; //选中查找到的节点
                            }
                        }
                    }
                    tv.SelectedNode.Nodes.Add(tn);
                }
                //tv.ExpandAll();//展开TreeView
                tv.SelectedNode = tv.TopNode; //最顶端节点选中
            }
[/codes]