Droptree with multiple datasources

Question

I have a drop tree and my client wants to be able to have the possibility to choose from two folders. We have a multi site and the structure looks like this:

Site 1 Data FolderHeWantsToChose

Site 2 Data FolderHeWantsToChose

I have tried something like this:

datasource=/sitecore/content/Site 1/Data/FolderHeWantsToChose&
datasource=/sitecore/content/Site 2/Data/FolderHeWantsToChose

and

/sitecore/content/Site 1/Data/FolderHeWantsToChose|/sitecore/content/Site 2/Data/FolderHeWantsToChose

and

ancestor::*[@@templatename='Site']/Data/FolderHeWantsToChose/*

but I can't find any good query to display only the folders and not the whole Sitecore tree.

Answer 1

As far I see you have 2 sites with same structure.

On your Datasource you make a small mistake, your query must be :

query:./ancestor-or-self::*[@@templatename='Site']/Data/FolderHeWantsToChose

A droptree is pointing to an item not to childs of an item.

Please see Datasource Properies of class Sitecore.Shell.Applications.ContentEditor.Tree (this is used for Droptree) :

 public string Source
    {
        get
        {
            return StringUtil.GetString(new string[]
            {
                this._source
            });
        }
        set
        {
            Assert.ArgumentNotNull(value, "value");
            if (!value.StartsWith("query:", StringComparison.InvariantCulture))
            {
                this._source = value;
                return;
            }
            Item item = Client.ContentDatabase.GetItem(this.ItemID);
            if (item == null)
            {
                return;
            }
            Item item2 = item.Axes.SelectSingleItem(value.Substring("query:".Length));
            if (item2 == null)
            {
                return;
            }
            this._source = item2.ID.ToString();
        }
    }

Answer 2

I just copy the answer from this blogpost - http://kamsar.net/index.php/2015/05/A-Multiple-Root-Treelist-Field

Sitecore itself provides a MultiRootTreeList control that is used for rendering the insert data source item dialog (which supports multiple roots).

Implementation (https://gist.github.com/kamsar/33d1245ffdb630b1f126):

using System;
using System.Linq;
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;

namespace Kamsar.FieldTypes
{
    /// <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
    {
        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 Sitecore.Web.UI.WebControls.MultiRootTreeview();
                impostor.ID = existingTreeView.ID;
                impostor.DblClick = existingTreeView.DblClick;
                impostor.Enabled = existingTreeView.Enabled;
                impostor.DisplayFieldName = existingTreeView.DisplayFieldName;

                // parse the data source and create appropriate data contexts out of it
                var dataContexts = 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);
            }
        }

        /// <summary>
        /// Parses multiple source roots into discrete data context controls (e.g. 'dataSource=/sitecore/content|/sitecore/media library')
        /// </summary>
        /// <param name="originalDataContext">The original data context the base control generated. We reuse some of its property values.</param>
        /// <returns></returns>
        protected virtual DataContext[] ParseDataContexts(DataContext originalDataContext)
        {
            return new ListString(DataSource).Select(x => CreateDataContext(originalDataContext, x)).ToArray();
        }

        /// <summary>
        /// Creates a DataContext control for a given Sitecore path data source
        /// </summary>
        protected virtual DataContext CreateDataContext(DataContext baseDataContext, string dataSource)
        {
            DataContext dataContext = new DataContext();
            dataContext.ID = GetUniqueID("D");
            dataContext.Filter = baseDataContext.Filter;
            dataContext.DataViewName = "Master";
            if (!string.IsNullOrEmpty(DatabaseName))
            {
                dataContext.Parameters = "databasename=" + DatabaseName;
            }
            dataContext.Root = dataSource;
            dataContext.Language = Language.Parse(ItemLanguage);

            return dataContext;
        }
    }
}