R – Inconsistent display behavior for Quick Launch menu in MOSS 2007

I followed @Nat's guidance into the murky world Sharepoint webparts to achieve the behavior I described above. My approach was to roll my own version of the MossMenu webpart that Microsoft has released through the ECM Team Blog. This code is based on the native AspMenu control. I used this control to "intercept" the native SiteMapDataSource injected into through DataSourceId attribute in the markup and create a new XML data source to exhibit the desired behavior. I've included the final source code at the end of this wordy answer. Here are the bits from the master page markup:

<%@ Register TagPrefix="myCustom" Namespace="YourCompany.CustomWebParts"
   Assembly="YourCompany.CustomWebParts, Version=1.0.0.0, Culture=neutral,
   PublicKeyToken=9f4da00116c38ec5" %>

...

<myCustom:MossMenu ID="CurrentNav" runat="server" datasourceID="SiteMapDS"
    orientation="Vertical" UseCompactMenus="true" StaticDisplayLevels="6"
    MaximumDynamicDisplayLevels="0" StaticSubMenuIndent="5" ItemWrap="false"
    AccessKey="3" CssClass="leftNav"
    SkipLinkText="<%$Resources:cms,masterpages_skiplinktext%>">
    <LevelMenuItemStyles>
        <asp:MenuItemStyle CssClass="Nav" />
        <asp:MenuItemStyle CssClass="SecNav" />
    </LevelMenuItemStyles>
    <StaticHoverStyle CssClass="leftNavHover"/>
    <StaticSelectedStyle CssClass="leftNavSelected"/>
    <DynamicMenuStyle CssClass="leftNavFlyOuts" />
    <DynamicMenuItemStyle CssClass="leftNavFlyOutsItem"/>
    <DynamicHoverStyle CssClass="leftNavFlyOutsHover"/>
</myCustom:MossMenu>

<PublishingNavigation:PortalSiteMapDataSource ID="SiteMapDS" Runat="server"
     SiteMapProvider="CurrentNavSiteMapProvider" EnableViewState="true"
     StartFromCurrentNode="true" ShowStartingNode="false"/>

...

I followed the excellent step-by-step instructions to create my custom web part in the comments section of the MossMenu webpart at "Wednesday, September 19, 2007 7:20 AM by Roel". In my googling, I also found something to configure a Sharepoint site to display exceptions in the same lovely way that ASP.NET does by making the web.config changes here.

I decided to call my custom behavior a "compact menu" so I created a UseCompactMenus property on the control. If you don't set this attribute in the markup to true, the control will behave identically to an AspMenu control.

My application has the user always starting from the home page at the site map root. I can have the custom control store the initial (complete) site map when the root page is displayed. This is stored in a static string for use in the customizing behavior. If you application doesn't follow this assumption, the control will not work as expected.

On the initial application page, only the direct child pages to the root page are displayed in the menu. Clicking on these menu nodes will open all the child nodes under it but keeps the sibling nodes "closed". If you click on one of the other sibling nodes, it collapses the current node and it opens the newly selected node. That's it, enjoy!!

using System;
using System.Text;
using System.ComponentModel;
using System.Collections.Generic;
using System.Security.Permissions;
using System.Xml;
using System.Xml.Serialization;

using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.Design.WebControls;

using Microsoft.SharePoint;
using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.Security;

namespace YourCompany.CustomWebParts
{
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
    [SharePointPermission(SecurityAction.LinkDemand, ObjectModel = true)]
    [SharePointPermission(SecurityAction.InheritanceDemand, ObjectModel = true)]
    [Designer(typeof(MossMenuDesigner))]
    [ToolboxData("<{0}:MossMenu runat=\"server\" />")]
    public class MossMenu : System.Web.UI.WebControls.Menu
    {
        private string idPrefix;

        // a url->menuItem dictionary
        private Dictionary<string, System.Web.UI.WebControls.MenuItem> menuItemDictionary =
            new Dictionary<string, System.Web.UI.WebControls.MenuItem>(StringComparer.OrdinalIgnoreCase);

        private bool customSelectionEnabled = true;
        private bool selectStaticItemsOnly = true;

        private bool performTargetBinding = true;

        //** Variables used for compact menu behavior **//
        private bool useCompactMenus = false;
        private static bool showStartingNode;
        private static string originalSiteMap;

        /// <summary>
        /// Controls whether or not the control performs compacting of the site map to display only ancestor and child nodes of the selected and first level root childern.
        /// </summary>
        [Category("Behavior")]
        public bool UseCompactMenus
        {
            get
            {
                return this.useCompactMenus;
            }
            set
            {
                this.useCompactMenus = value;
            }
        }

        /// <summary>
        /// Controls whether or not the control performs custom selection/highlighting.
        /// </summary>
        [Category("Behavior")]
        public bool CustomSelectionEnabled
        {
            get
            {
                return this.customSelectionEnabled;
            }
            set
            {
                this.customSelectionEnabled = value;
            }
        }

        /// <summary>
        /// Controls whether only static items may be selected or if
        /// dynamic (fly-out) items may be selected too.
        /// </summary>
        [Category("Behavior")]
        public bool SelectStaticItemsOnly
        {
            get
            {
                return this.selectStaticItemsOnly;
            }
            set
            {
                this.selectStaticItemsOnly = value;
            }
        }

        /// <summary>
        /// Controls whether or not to bind the Target property of any menu
        /// items to the Target property in the SiteMapNode's Attributes
        /// collection.
        /// </summary>
        [Category("Behavior")]
        public bool PerformTargetBinding
        {
            get
            {
                return this.performTargetBinding;
            }
            set
            {
                this.performTargetBinding = value;
            }
        }

        /// <summary>
        /// Gets the ClientID of this control. 
        /// </summary>
        public override string ClientID
        {
            [SharePointPermission(SecurityAction.Demand, ObjectModel = true)]
            get
            {
                if (this.idPrefix == null)
                {
                    this.idPrefix = SPUtility.GetNewIdPrefix(this.Context);
                }

                return SPUtility.GetShortId(this.idPrefix, this);
            }
        }

        [SharePointPermission(SecurityAction.Demand, ObjectModel = true)]
        protected override void OnMenuItemDataBound(MenuEventArgs e)
        {
            base.OnMenuItemDataBound(e);

            if (this.customSelectionEnabled)
            {
                // store in the url->item dictionary
                this.menuItemDictionary[e.Item.NavigateUrl] = e.Item;
            }

            if (this.performTargetBinding)
            {
                // try to bind to the Target property if the data item is a SiteMapNode
                SiteMapNode smn = e.Item.DataItem as SiteMapNode;
                if (smn != null)
                {
                    string target = smn["Target"];
                    if (!string.IsNullOrEmpty(target))
                    {
                        e.Item.Target = target;
                    }
                }
            }
        }

        /// <id guid="08e034e7-5872-4a31-a771-84cac1dcd53d" />
        /// <owner alias="MarkWal">
        /// </owner>
        [SharePointPermission(SecurityAction.Demand, ObjectModel = true)]
        protected override void OnPreRender(System.EventArgs e)
        {

            SiteMapDataSource dataSource = this.GetDataSource() as SiteMapDataSource;
            SiteMapProvider provider = (dataSource != null) ? dataSource.Provider : null;

            if (useCompactMenus && dataSource != null && provider != null)
            {
                showStartingNode = dataSource.ShowStartingNode;

                SiteMapNodeCollection rootChildNodes = provider.RootNode.ChildNodes;

                if (provider.CurrentNode.Equals(provider.RootNode))
                {
                    //** Store original site map for future use in compacting menus **//
                    if (originalSiteMap == null)
                    {
                        //Store original SiteMapXML for future adjustments:
                        XmlDocument newSiteMapDoc = new XmlDocument();
                        newSiteMapDoc.LoadXml("<?xml version='1.0' ?>"
                            + "<siteMapNode title='" + provider.RootNode.Title
                            + "' url='" + provider.RootNode.Url
                            + "' />");

                        foreach (SiteMapNode node in rootChildNodes)
                        {
                            XmlNode newNode = GetXmlSiteMapNode(newSiteMapDoc.DocumentElement, node);

                            newSiteMapDoc.DocumentElement.AppendChild(newNode);

                            //Create XML for all the child nodes for selected menu item:
                            NavigateSiteMap(newNode, node);
                        }

                        originalSiteMap = newSiteMapDoc.OuterXml;
                    }

                    //This is set to only display the child nodes of the root node on first view:
                    this.StaticDisplayLevels = 1;
                }
                else
                {
                    //
                    //Adjust site map for this page
                    //
                    XmlDocument newSiteMapDoc = InitializeNewSiteMapXml(provider, rootChildNodes);

                    //Clear the current default site map:
                    this.DataSourceID = null;

                    //Create the new site map data source
                    XmlDataSource newSiteMap = new XmlDataSource();
                    newSiteMap.ID = "XmlDataSource1";
                    newSiteMap.EnableCaching = false; //Required to prevent redisplay of the previous menu

                    //Add bindings for dynamic site map:
                    MenuItemBindingCollection bindings = this.DataBindings;
                    bindings.Clear();

                    MenuItemBinding binding = new MenuItemBinding();
                    binding.DataMember = "siteMapNode";
                    binding.TextField = "title";
                    binding.Text = "title";
                    binding.NavigateUrlField = "url";
                    binding.NavigateUrl = "url";
                    binding.ValueField = "url";
                    binding.Value = "url";

                    bindings.Add(binding);

                    //Bind menu to new site map:
                    this.DataSource = newSiteMap;

                    //Assign the newly created dynamic site map:
                    ((XmlDataSource)this.DataSource).Data = newSiteMapDoc.OuterXml;

                    /** this expression removes the root if initialized: **/
                    if (!showStartingNode)
                        ((XmlDataSource)this.DataSource).XPath = "/siteMapNode/siteMapNode";

                    /** Re-initialize menu data source with new site map: **/
                    this.DataBind();

                    /** Find depth of current node: **/
                    int depth = 0;
                    SiteMapNode currNode = provider.CurrentNode;
                    do
                    {
                        depth++;
                        currNode = currNode.ParentNode;
                    }
                    while (currNode != null);

                    //Set the StaticDisplayLevels to match the current depth:
                    if (depth >= this.StaticDisplayLevels)
                        this.StaticDisplayLevels = depth;
                }
            }

            base.OnPreRender(e);

            // output some script to override the default menu flyout behaviour; this helps to avoid
            // intermittent "Operation Aborted" errors
            Page.ClientScript.RegisterStartupScript(
                typeof(MossMenu),
                "overrideMenu_HoverStatic",
                "if (typeof(overrideMenu_HoverStatic) == 'function' && typeof(Menu_HoverStatic) == 'function')\n" +
                "{\n" +
                    "_spBodyOnLoadFunctionNames.push('enableFlyoutsAfterDelay');\n" +
                    "Menu_HoverStatic = overrideMenu_HoverStatic;\n" +
                "}\n",
                true);

            // output some script to avoid a known issue with SSL Termination and the ASP.NET
            // Menu implementation. http://support.microsoft.com/?id=910444
            Page.ClientScript.RegisterStartupScript(
                typeof(MossMenu),
                "MenuHttpsWorkaround_" + this.ClientID,
                this.ClientID + "_Data.iframeUrl='/_layouts/images/blank.gif';",
                true);

            // adjust the fly-out indicator arrow direction for locale if not already set
            if (this.Orientation == System.Web.UI.WebControls.Orientation.Vertical &&
                ((string.IsNullOrEmpty(this.StaticPopOutImageUrl) && this.StaticEnableDefaultPopOutImage) ||
                    (string.IsNullOrEmpty(this.DynamicPopOutImageUrl) && this.DynamicEnableDefaultPopOutImage)))
            {
                SPWeb currentWeb = SPContext.Current.Web;
                if (currentWeb != null)
                {
                    uint localeId = currentWeb.Language;

                    bool isBidiWeb = SPUtility.IsRightToLeft(currentWeb, currentWeb.Language);

                    string arrowUrl = "/_layouts/images/" + (isBidiWeb ? "largearrowleft.gif" : "largearrowright.gif");

                    if (string.IsNullOrEmpty(this.StaticPopOutImageUrl) && this.StaticEnableDefaultPopOutImage)
                    {
                        this.StaticPopOutImageUrl = arrowUrl;
                    }
                    if (string.IsNullOrEmpty(this.DynamicPopOutImageUrl) && this.DynamicEnableDefaultPopOutImage)
                    {
                        this.DynamicPopOutImageUrl = arrowUrl;
                    }
                }
            }

            if (provider == null)
            {
                // if we're not attached to a SiteMapDataSource we'll just leave everything alone
                return;
            }
            else if (this.customSelectionEnabled)
            {
                MenuItem selectedMenuItem = this.SelectedItem;
                SiteMapNode currentNode = provider.CurrentNode;

                // if no menu item is presently selected, we need to work our way up from the current 
                // node until we can find a node in the menu item dictionary
                while (selectedMenuItem == null && currentNode != null)
                {
                    this.menuItemDictionary.TryGetValue(currentNode.Url, out selectedMenuItem);

                    currentNode = currentNode.ParentNode;
                }

                if (this.selectStaticItemsOnly)
                {
                    // only static items may be selected, keep moving up until we find an item
                    // that falls within the static range
                    while (selectedMenuItem != null && selectedMenuItem.Depth >= this.StaticDisplayLevels)
                    {
                        selectedMenuItem = selectedMenuItem.Parent;
                    }

                    // if we found an item to select, go ahead and select (highlight) it
                    if (selectedMenuItem != null && selectedMenuItem.Selectable)
                    {
                        selectedMenuItem.Selected = true;
                    }
                }
            }
        }

        private XmlDocument InitializeNewSiteMapXml(SiteMapProvider provider, SiteMapNodeCollection rootChildNodes)
        {
            /** Find the level 1 ancestor node of the current node: **/
            SiteMapNode levelOneAncestorOfSelectedNode = null;
            SiteMapNode currNode = provider.CurrentNode;
            do
            {
                levelOneAncestorOfSelectedNode = (currNode.ParentNode == null ? levelOneAncestorOfSelectedNode : currNode);
                currNode = currNode.ParentNode;
            }
            while (currNode != null);

            /** Initialize base SiteMapXML **/
            XmlDocument newSiteMapDoc = new XmlDocument();
            newSiteMapDoc.LoadXml(originalSiteMap);

            /** Prune out the childern nodes that shouldn't display: **/
            currNode = provider.CurrentNode;
            do
            {
                if (currNode.ParentNode != null)
                {
                    SiteMapNodeCollection currNodeSiblings = currNode.ParentNode.ChildNodes;
                    foreach (SiteMapNode siblingNode in currNodeSiblings)
                    {
                        if (siblingNode.HasChildNodes)
                        {
                            if (provider.CurrentNode.Equals(siblingNode))
                            {
                                //Remove all the childerns child nodes from display:
                                SiteMapNodeCollection currNodesChildren = siblingNode.ChildNodes;
                                foreach (SiteMapNode childNode in currNodesChildren)
                                {
                                    XmlNode currentXmNode = GetCurrentXmlNode(newSiteMapDoc, childNode);

                                    DeleteChildNodes(currentXmNode);
                                }
                            }
                            else if (!provider.CurrentNode.IsDescendantOf(siblingNode)
                                && !levelOneAncestorOfSelectedNode.Equals(siblingNode))
                            {
                                XmlNode currentXmNode = GetCurrentXmlNode(newSiteMapDoc, siblingNode);

                                DeleteChildNodes(currentXmNode);
                            }
                        }
                    }
                }

                currNode = currNode.ParentNode;
            }
            while (currNode != null);

            return newSiteMapDoc;
        }

        private XmlNode GetCurrentXmlNode(XmlDocument newSiteMapDoc, SiteMapNode node)
        {
            //Find this node in the original site map:
            XmlNode currentXmNode = newSiteMapDoc.DocumentElement.SelectSingleNode(
                "//siteMapNode[@url='"
                + node.Url
                + "']");
            return currentXmNode;
        }

        private void DeleteChildNodes(XmlNode currentXmNode)
        {
            if (currentXmNode != null && currentXmNode.HasChildNodes)
            {
                //Remove child nodes:
                XmlNodeList xmlNodes = currentXmNode.ChildNodes;
                int lastNodeIndex = xmlNodes.Count - 1;
                for (int i = lastNodeIndex; i >= 0; i--)
                {
                    currentXmNode.RemoveChild(xmlNodes[i]);
                }
            }
        }
        private XmlNode GetXmlSiteMapNode(XmlNode currentDocumentNode, SiteMapNode currentNode)
        {
            XmlElement newNode = currentDocumentNode.OwnerDocument.CreateElement("siteMapNode");

            XmlAttribute newAttr = currentDocumentNode.OwnerDocument.CreateAttribute("title");
            newAttr.InnerText = currentNode.Title;
            newNode.Attributes.Append(newAttr);

            newAttr = currentDocumentNode.OwnerDocument.CreateAttribute("url");
            newAttr.InnerText = currentNode.Url;
            newNode.Attributes.Append(newAttr);

            return newNode;
        }

        private void NavigateSiteMap(XmlNode currentDocumentNode, SiteMapNode currentNode)
        {
            foreach (SiteMapNode node in currentNode.ChildNodes)
            {
                //Add this node to structure:
                XmlNode newNode = GetXmlSiteMapNode(currentDocumentNode, node);
                currentDocumentNode.AppendChild(newNode);

                if (node.HasChildNodes)
                {
                    //Make a recursive call to add any child nodes:
                    NavigateSiteMap(newNode, node);
                }
            }
        }
    }

    [PermissionSet(SecurityAction.LinkDemand, Name = "FullTrust")]
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2117:AptcaTypesShouldOnlyExtendAptcaBaseTypes")]
    public sealed class MossMenuDesigner : MenuDesigner
    {
        [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
        protected override void DataBind(BaseDataBoundControl dataBoundControl)
        {
            try
            {
                dataBoundControl.DataBind();
            }
            catch
            {
                base.DataBind(dataBoundControl);
            }
        }

        [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
        public override string GetDesignTimeHtml()
        {
            System.Web.UI.WebControls.Menu menu = (System.Web.UI.WebControls.Menu)ViewControl;
            int oldDisplayLevels = menu.MaximumDynamicDisplayLevels;
            string designTimeHtml = string.Empty;

            try
            {
                menu.MaximumDynamicDisplayLevels = 0;

                // ASP.NET MenuDesigner has some dynamic/static item trick in design time
                // to show dynamic item in design time. We only want to show preview without
                // dynamic menu items.
                designTimeHtml = base.GetDesignTimeHtml();
            }
            catch (Exception e)
            {
                designTimeHtml = GetErrorDesignTimeHtml(e);
            }
            finally
            {
                menu.MaximumDynamicDisplayLevels = oldDisplayLevels;
            }

            return designTimeHtml;
        }
    }
}