给TreeNode加一个TreeNode,出错的有木有.解决思路

<asp:TreeView ID="TreeView1" runat="server">            <Nodes>            </Nodes></asp:TreeView>

        protected void Page_Load(object sender, EventArgs e)        {            if (!IsPostBack)            {                TreeNode root = new TreeNode("用户管理");                TreeNode node = new TreeNode("我的空间");                node.Target = "rightframe";                node.NavigateUrl = "/User/Space.aspx?name=" + Session["UserName"];                this.TreeView1.Nodes.Add(root);                this.root.Add(node);            }        }