treeview中在节点设置NavigateUrl后,SelectedNodeStyle不起作用

treeview中在节点设置NavigateUrl后,SelectedNodeStyle不起作用 了
<asp:TreeView ID="TVLeftMenu" runat="server" ImageSet="Msdn" NodeIndent="10" 
                ShowLines="True" onselectednodechanged="TVLeftMenu_SelectedNodeChanged" >
        <ParentNodeStyle Font-Bold="False" />
        <HoverNodeStyle BackColor="#CCCCCC" Font-Underline="True" ForeColor="White" />
        <SelectedNodeStyle BackColor="#CCCCCC" Font-Underline="False" ForeColor="White" HorizontalPadding="3px" VerticalPadding="2px" />
        <NodeStyle Font-Names="Verdana" ForeColor="Black" HorizontalPadding="3px" NodeSpacing="1px" VerticalPadding="3px" />
         
         <Nodes>
         <asp:TreeNode Text="Expense Report " Value="Report" NavigateUrl="www.baidu.com" />
         <asp:TreeNode Text="Approval" Value="Approval" NavigateUrl="~www.baidu.com" />
         <asp:TreeNode Text="Report" Value="Report" NavigateUrl="www.baidu.com" />
         <asp:TreeNode Text="Settings" Value="Settings" Expanded="true" >
             <asp:TreeNode Text="Entity" Value="Entity" NavigateUrl="www.baidu.com" />
             <asp:TreeNode Text="Department" Value="Dept" NavigateUrl="www.baidu.com" />
             <asp:TreeNode Text="Employee" Value="Emp" NavigateUrl="www.baidu.com" />
             <asp:TreeNode Text="Expense Item" Value="RItem" NavigateUrl="www.baidu.com" />            
             <asp:TreeNode Text="Policy" Value="Policy" NavigateUrl="www.baidu.com" />
             <asp:TreeNode Text="Vendor" Value="Vendor" NavigateUrl="www.baidu.com" />
         </asp:TreeNode>
         </Nodes> 
        </asp:TreeView> 不使用NavigateUrl的时候  SelectedNodeStyle是起作用的 麻烦问下是什么原因  应该怎么解决?