How to pop up different text base on the selected TreeNode?

[vincent90152900]

How to pop up different text base on the selected TreeNode?
I want to pop up different Text base on the selected TreeNode of the TreeView component. So, I create a TreeView and a ModalPopupExtender. Following is my codes.

Default.aspx
[HTML] <asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:TreeView ID="TreeView1" runat="server" OnSelectedNodeChanged="TreeView1_SelectedNodeChang ed">
<Nodes>
<asp:TreeNode Text="New Node" Value="New Node"></asp:TreeNode>
<asp:TreeNode Text="New Node" Value="New Node"></asp:TreeNode>
</Nodes>
</asp:TreeView>
<cc1:ModalPopupExtender ID="ModalPopupExtender1" runat="server" TargetControlID="TreeView1"
PopupControlID="Panel1">
</cc1:ModalPopupExtender>
<asp:Panel ID="Panel1" runat="server" Height="50px" Width="125px">
&nbsp;
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label></asp:Panel>[/HTML]

Default.aspx.cs

        protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
        {
            this.Label1.Text = this.TreeView1.SelectedNode.Value.ToString();
        }

When I click the TreeView component, the panel is pop up, but the text of label in the panel is not change. Does anyone know why, and how to solve this problem?