Multi-root treelist with queries

Question

I'm trying to use the Multi-root treelist that Kam Figy made and that Zachary Kniebel extended. I used this guide to add the Field-type to the Core database.

All is well, until I put query: anywhere in the fields source. In the use-case I have I need to have at least one of the two roots be a query like so:

query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets

The other root can be an absolute path if need be, or a query, for this example let's say it's the content-root, I've tried these values in the Source-field of the template-field with Multi-root Treelist:

query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|/sitecore/content
// yields only 1st root, the query, content-root isn't there.
datasource=query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|/sitecore/content
// yields 2nd root correctly, 1st root defaults to /sitecore root
datasource=query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|datasource=/sitecore/content
// both roots are now defaulting to /sitecore root
datasource=query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|datasource=query:/sitecore/content
// again both roots now /sitecore root
query:./ancestor-or-self::*[@@templatename='Website']/Sitedata/Facets|query:/sitecore/content
// yields nothing, no roots shown, completely empty field in content-editor

Whether I use Kam's code or Zachary's code, the results are the same. What's going on?

EDIT:

I've done some digging and I think I've narrowed the problem down somewhat. If the value starts with query: then Sitecore does the parsing and disregards anything after the | before passing it on to the custom code. So I'm using the 2nd query, with format datasource=query:./ancestor-etc|/sitecore/content. And I'm using Kam's code-base extended only with the parts of Zachary's code that parse the query: as Kam's code didn't do that. So this is my version of Kam's CreateDataContext:

protected virtual DataContext CreateDataContext(DataContext baseDataContext, string dataSource)
{
    Item datasourceItem = null;
    if (dataSource.StartsWith("query:"))
    {
        try
        {
            var currentItem = Sitecore.Context.ContentDatabase.GetItem(this.ItemID);
            var results = LookupSources.GetItems(currentItem, dataSource);
            datasourceItem = results.FirstOrDefault(item => item != null);
            dataSource = datasourceItem.Paths.FullPath;
        }
        catch (Exception ex)
        {
            Log.Error($"Treelist field failed to execute query: '{dataSource}'", ex, this);
        }
    }

    DataContext dataContext = new DataContext
    {
        ID = GetUniqueID("D"),
        Filter = baseDataContext.Filter,
        DataViewName = "Master",
        Root = dataSource,
        Language = Language.Parse(this.ItemLanguage)
    };

    if (!string.IsNullOrEmpty(this.DatabaseName))
    {
        dataContext.Parameters = "databasename=" + this.DatabaseName;
    }

    return dataContext;
}

Stepping into the code, it looks like LookupSources.GetItems() doesn't like my query as it returns an empty Item-array. To be clear, this query works perfectly fine when used as a datasource for a controller rendering, so it's not the query itself.

I tried the following in the debugger's Immediate Window while pauzed right after the LookupSources.GetItems() line above:

LookupSources.GetItems(currentItem, "query:.");
'LookupSources.GetItems(currentItem, "query:.")' threw an exception of type 'Sitecore.Exceptions.LookupSourceException'
    Data: {System.Collections.ListDictionaryInternal}
    HResult: -2146233088
    HelpLink: null
    InnerException: {"Index was outside the bounds of the array."}
    InnerMessage: "Index was outside the bounds of the array."
    Message: "Invalid lookup source \"query:.\": Index was outside the bounds of the array.."
// ^ so the "query:" part should be trimmed, aha

LookupSources.GetItems(currentItem, ".");
{Sitecore.Data.Items.Item[1]}
    "Werken bij banner": Werken bij banner (en#1@master), id: {7D9F219F-19EA-4CEB-AC8B-BCE4894D71B1}
// This is the only child-item of the current item. I kinda expected the current Item, not its children.
// But at least LookupSources isn't completely kaput

LookupSources.GetItems(currentItem, "..");
{Sitecore.Data.Items.Item[2]}
// This is the current Item and its only sibling, so far so good

LookupSources.GetItems(currentItem, "./ancestor-or-self::*[@@templatename='website']/sitedata/facets");
{Sitecore.Data.Items.Item[0]}
// Nothing

LookupSources.GetItems(currentItem, "./ancestor-or-self::*");
{Sitecore.Data.Items.Item[0]}
// Nothing still?

LookupSources.GetItems(currentItem, "./ancestor::*");
{Sitecore.Data.Items.Item[57]}
// So maybe ancestor-or-self is kaput and I should use just ancestor?

LookupSources.GetItems(currentItem, "./ancestor::*[@@templatename='website']");
{Sitecore.Data.Items.Item[0]}
// Nope, still kaput

LookupSources.GetItems(currentItem, "./ancestor::*[@@templateid='{299B2290-E128-4633-8F9A-DCCC1CCBA9DE}']");
{Sitecore.Data.Items.Item[0]}
// Google searches use @@templateid in stead of @@templatename, but nope.

LookupSources.GetItems(currentItem, "./ancestor-or-self::*[@@templateid='{299B2290-E128-4633-8F9A-DCCC1CCBA9DE}']");
{Sitecore.Data.Items.Item[0]}
// ancestor-or-self combined with @@templateid just to be sure, alas

// maybe the string isn't parsed correctly before sending it to GetItems() to begin with so lets make it @""
LookupSources.GetItems(currentItem, @"./ancestor::*[@@templateid='{299B2290-E128-4633-8F9A-DCCC1CCBA9DE}']");
{Sitecore.Data.Items.Item[0]}
LookupSources.GetItems(currentItem, @"./ancestor::*[@@templatename='website']");
{Sitecore.Data.Items.Item[0]}
// still nothing...

TL;DR: LookupSources.GetItems() doesn't seem to do ancestor-or-self and doesn't do *[@@templatename='Website'] or *[@@templateid='{299B2290-E128-4633-8F9A-DCCC1CCBA9DE}']. What to do about that or try differently?

Answer 1

I fixed the issue myself with some interesting findings. The customer this concerns is running Sitecore 8.1, different versions might yield different results.

As mentioned in the EDIT's debug copy-pasta, LookupSources.GetItems() does not return the items found with the query, but rather those items' children. As well it doesn't support ancestor-or-self::, only ancestor::. This renders LookupSources.GetItems() useless for me. (Frankly I would consider different implementations of query:-resolving within the same CMS harmful)

In stead I took code from Sitecore's Habitat project to find the correct Item by giving the query-string either to the contextItem's .Axes.SelectItems() or .Database.SelectItems():

query.StartsWith("./", StringComparison.OrdinalIgnoreCase)
    ? currentItem.Axes.SelectItems(query)
    : currentItem.Database.SelectItems(query);

But, this doesn't entirely fix the issue, because Sitecore preprocesses the value given to the above Custom Field code by putting it all in lower case. This is a (big, huge, glaring) problem, because @@templatename might contain upper case letters like in my case 'Website' and @@templateid definitely contains a Guid with upper case letter A-F and matching to a lower case guid does not work.

So you need to use @@templatekey, which is the templatename in lower case.

Looking at the Sitecore documentation, this lower case issue renders a bunch of @@var's useless, like @@id, @@name (use @@key in stead) or any @fieldname of fields where the value might contain letters.

So I switched to using @@templatekey and used Kam's code as a basis, only adding the parts from Zachary that I liked, needed and that worked:

namespace Aeres.Foundation.SitecoreExtensions.CustomFields
{
    using System;
    using System.Linq;
    using Sitecore.Data.Items;
    using Sitecore.Diagnostics;
    using Sitecore.Globalization;
    using Sitecore.Shell.Applications.ContentEditor;
    using Sitecore.Text;
    using Sitecore.Web;
    using Sitecore.Web.UI.HtmlControls;
    using Sitecore.Web.UI.WebControls;

    /// <summary>
    /// This field type is like a tree list, but you can specify more than one root item to select from (for example, videos or photos)
    /// The data source roots are specified using pipe delimiting just like regular Sitecore Query language
    /// </summary>
    public class MultiRootTreeList : TreeList
    {
        private const string QueryPrefix = "query:";

        protected override void OnLoad(EventArgs args)
        {
            Assert.ArgumentNotNull(args, "args");
            base.OnLoad(args);

            if (!Sitecore.Context.ClientPage.IsEvent)
            {
                // find the existing TreeviewEx that the base OnLoad added, get a ref to its parent, and remove it from controls
                var existingTreeView = (TreeviewEx)WebUtil.FindControlOfType(this, typeof(TreeviewEx));
                var treeviewParent = existingTreeView.Parent;

                existingTreeView.Parent.Controls.Clear(); // remove stock treeviewex, we replace with multiroot

                // find the existing DataContext that the base OnLoad added, get a ref to its parent, and remove it from controls
                var dataContext = (DataContext)WebUtil.FindControlOfType(this, typeof(DataContext));
                var dataContextParent = dataContext.Parent;

                dataContextParent.Controls.Remove(dataContext); // remove stock datacontext, we parse our own

                // create our MultiRootTreeview to replace the TreeviewEx
                var impostor = new EnhancedMultiRootTreeview
                {
                    ID = existingTreeView.ID,
                    DblClick = existingTreeView.DblClick,
                    Enabled = existingTreeView.Enabled,
                    DisplayFieldName = existingTreeView.DisplayFieldName
                };

                // parse the data source and create appropriate data contexts out of it
                var dataContexts = this.ParseDataContexts(dataContext);

                impostor.DataContext = string.Join("|", dataContexts.Select(x => x.ID));
                foreach (var context in dataContexts)
                {
                    dataContextParent.Controls.Add(context);
                }

                // inject our replaced control where the TreeviewEx originally was
                treeviewParent.Controls.Add(impostor);
            }
        }

        protected virtual DataContext[] ParseDataContexts(DataContext originalDataContext)
        {
            return new ListString(this.DataSource).Select(x => this.CreateDataContext(originalDataContext, x)).ToArray();
        }

        protected virtual DataContext CreateDataContext(DataContext baseDataContext, string dataSource)
        {
            Item dataSourceItem = null;
            if (dataSource.StartsWith(QueryPrefix))
            {
                try
                {
                    var query = dataSource.Substring(QueryPrefix.Length);
                    var currentItem = Sitecore.Context.ContentDatabase.GetItem(this.ItemID);
                    var results = query.StartsWith("./", StringComparison.OrdinalIgnoreCase)
                        ? currentItem.Axes.SelectItems(query)
                        : currentItem.Database.SelectItems(query);
                    dataSourceItem = results.FirstOrDefault(item => item != null);
                    dataSource = dataSourceItem.Paths.FullPath;
                }
                catch (Exception ex)
                {
                    Log.Error($"Treelist field failed to execute query: '{dataSource}'", ex, this);
                }
            }

            DataContext dataContext = new DataContext
            {
                ID = GetUniqueID("D"),
                Filter = baseDataContext.Filter,
                DataViewName = "Master",
                Root = dataSource,
                Language = Language.Parse(this.ItemLanguage)
            };

            if (!string.IsNullOrEmpty(this.DatabaseName))
            {
                dataContext.Parameters = "databasename=" + this.DatabaseName;
            }

            return dataContext;
        }
    }
}

and:

namespace Aeres.Foundation.SitecoreExtensions.CustomFields
{
    using Sitecore.Data.Items;
    using Sitecore.Diagnostics;
    using Sitecore.Web.UI.WebControls;

    public class EnhancedMultiRootTreeview : MultiRootTreeview
    {
        protected override string GetHeaderValue(Item item)
        {
            Assert.ArgumentNotNull(item, "item");

            var nodeTitle = string.IsNullOrEmpty(this.DisplayFieldName) ? item.DisplayName : item[this.DisplayFieldName];
            nodeTitle = string.IsNullOrEmpty(nodeTitle) ? item.DisplayName : nodeTitle;

            // you can get fancy here and make the format of the nodeTitle manageable in config
            nodeTitle = $"{nodeTitle}  -  <span>({item.Paths.ContentPath})</span>";

            return nodeTitle;
        }
    }
}

Answer 2

Sorry to give a link-only answer, but this module is worth considering:

https://github.com/mikaelnet/sitecore-multi-treelist

Since it's wise to consider using TreeListEx field over TreeList due to the query performance cost to the Content Editor - if your source query happens to be expensive, it can have a very siginificant effect on performance. Therefore, when your field has a source with multiple queries which this can, then using a version of the field which enables editing via a separate window is a very good idea.