asp.net - 下拉菜单作为菜单控件asp.net

Question

我有一个简单的菜单控件这里是代码

<asp:menu id="mainMenu" runat="server" orientation="Horizontal" maximumdynamicdisplaylevels="0" skiplinktext="    " staticdisplaylevels="2" cssclass="menua" staticselectedstyle-forecolor="DarkBlue" staticselectedstyle-font-underline="true" onmenuitemclick="mainMenu_MenuItemClick">
 <Items>
     <asp:MenuItem Text="Management" Value="mTabManagement"  NavigateUrl="TabManagement.aspx">
         <asp:MenuItem  Text="Auditing" Value="mAuditing" NavigateUrl=""></asp:MenuItem>
         <asp:MenuItem Text="Billing" Value="mBilling" NavigateUrl=""></asp:MenuItem>
         <asp:MenuItem Text="Reporting/Services" Value="mServices" NavigateUrl=""></asp:MenuItem>
     </asp:MenuItem>
     <asp:MenuItem Text="Payment Plan)" Value="mPayment" NavigateUrl="PaymentPlan.aspx"></asp:MenuItem>
     <asp:MenuItem Text="Advocate" Value="mTabAdvocate" NavigateUrl="TabAdvocate.aspx"></asp:MenuItem>
     <asp:MenuItem Text="Pay" Value="mPay" NavigateUrl="HowItWorks.aspx"></asp:MenuItem>
     <asp:MenuItem Text="Parking Ticket Protection" Value="mProtection" NavigateUrl="Security.aspx"></asp:MenuItem>   
 </Items>         
 </asp:menu>

我该怎么做

 <asp:MenuItem Text="Management" Value="mTabManagement"/>

像下拉列表一样工作