Applies To: SharePoint 2010

The Top Link Bar (sometimes called the Tab Bar) allows you to include a mix of links and headers (with child links). By default, this results in a single sub menu and handles most situations well.

However, the need to have multiple levels (additional sub menus) often comes up. There are several solutions out there that suggest replacing the Top Navigation Menu control altogether using javascript or CSS menus. These work but are also totally unnecessary. The Top Link Bar uses a standard ASP.NET menu control and comes with several attributes that can be customized.

In the v4.master (SharePoint 2010) the section we’re interested in can be found inside the PlaceHolderTopNavBar ContentPlaceHolder (Specifically the SharePoint:AspMenu control TopNavigationMenuV4):

					<asp:ContentPlaceHolder id="PlaceHolderTopNavBar" runat="server">
					<h2 class="ms-hidden">
					<SharePoint:EncodedLiteral runat="server" text="<%$Resources:wss,topnav_pagetitle%>" EncodeMethod="HtmlEncode"/></h2>
							<asp:ContentPlaceHolder id="PlaceHolderHorizontalNav" runat="server">
<SharePoint:AspMenu
  ID="TopNavigationMenuV4"
  Runat="server"
  EnableViewState="false"
  DataSourceID="topSiteMap"
  AccessKey="<%$Resources:wss,navigation_accesskey%>"
  UseSimpleRendering="true"
  UseSeparateCss="false"
  Orientation="Horizontal"
  StaticDisplayLevels="2"
  MaximumDynamicDisplayLevels="1"
  SkipLinkText=""
  CssClass="s4-tn"/>
<SharePoint:DelegateControl runat="server" ControlId="TopNavigationDataSource" Id="topNavigationDelegate">
	<Template_Controls>
		<asp:SiteMapDataSource
		  ShowStartingNode="False"
		  SiteMapProvider="SPNavigationProvider"
		  id="topSiteMap"
		  runat="server"
		  StartingNodeUrl="sid:1002"/>
	</Template_Controls>
</SharePoint:DelegateControl>
							</asp:ContentPlaceHolder>
					</asp:ContentPlaceHolder>

The key attribute can be found on line 355 above. The MaximumDynamicDisplayLevels defaults to 1. Setting this to 2 or higher will control how many levels of sub menus you want to allow. Once you’ve made this change to your Master Page (saved, checked-in, and approved), SharePoint will be able to display multiple sub menus!

Unfortunately, the navigation settings found in Site Actions > Site Settings > Navigation (under Look and Feel) only allow top level Header entries and won’t display or allow you to edit navigation nodes at levels greater than 2:

So even though we made the correct change to the control we have no native way to edit these sub menus. Fortunately this can be done with PowerShell (Or just plain .NET) which will be the subject of the next post. However, this is a necessary first step towards Multi-Level Top Bar Links.