Get Personalised Datasource from a View Rendering

RenderingDatasourceHelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Sitecore.Data;
using Sitecore.Data.Items;
using Sitecore.Layouts;
using Sitecore.Rules;
using Sitecore.Rules.ConditionalRenderings;

namespace BlackTambourine.Core.Sitecore.Helpers
{
    /// <summary>
    /// Functions to get the Datasources for a particular instance of a Rendering
    /// based on these:
    /// https://blog.horizontalintegration.com/2015/09/08/programmatically-get-datasource-items-of-a-sitecore-item/
    /// https://blog.horizontalintegration.com/2015/09/08/programmatically-get-personalization-datasource-items-of-a-sitecore-item/
    /// </summary>
    public class RenderingDatasourceHelper
    {
        /// <summary>
        /// Get the Personalised Datasource(s) from a particular Placeholder and View Rendering on an item
        /// </summary>
        /// <param name="device"></param>
        /// <param name="i">Item which has the placeholder on it</param>
        /// <param name="placeholderName">Presentation Settings Placeholder Name</param>
        /// <param name="renderingId">ID of the View Rendering used in this Placeholder</param>
        /// <returns>List of Sitecore Items used as datasources in these View Renderings</returns>
        public static List<Item> GetPersonalisedPlaceHolderDatasourceItems(DeviceItem device, Item i, string placeholderName, ID renderingId)
        {
            var result = new List<Item>();
            var renderingReferences = GetRenderingReferences(device, i, placeholderName, renderingId).ToList();

            result = renderingReferences
                .SelectMany(x=> GetPersonalizationDataSourceItem(x, i))
                .Where(y => y != null)
                .ToList();
            return result;
        }

        #region Methods to get the Datasources

        private static IEnumerable<Item> GetPersonalizationDataSourceItem(RenderingReference reference, Item i)
        {
            var list = new List<Item>();

            //if no datasource
            if (reference == null)
            {
                return list; 
            }

            //else if no Personalisation is used, return the default datasource
            if (reference.Settings.Rules == null || reference.Settings.Rules.Count <= 0)
            {
                var item = GetDataSourceItem(reference);
                if (item != null)
                {
                    list.Add(item);
                }
                return list; 
            }


            //note: doesn't support personalisation of the component with multiple renderings
            var ruleContext = new ConditionalRenderingsRuleContext(new List<RenderingReference> {reference}, reference)
            {
                Item = i
            };

            reference.Settings.Rules.RunFirstMatching(ruleContext);
            list.Add(GetDataSourceItem(reference.Settings.DataSource, reference.Database));

            //else Get the Personalised datasource
            //foreach (var r in reference.Settings.Rules.Rules)
            //{


            //    if (r.Evaluate(ruleContext))
            //    {
            //        list.AddRange(r.Actions
            //            .OfType<SetDataSourceAction<ConditionalRenderingsRuleContext>>()
            //            .Select(setDataSourceAction => GetDataSourceItem(setDataSourceAction.DataSource, reference.Database))
            //            .Where(dataSourceItem => dataSourceItem != null));

            //        return list; //break from loop on first evaluated
            //    }
            //}
            return list;
        }

        private static IEnumerable<RenderingReference> GetRenderingReferences(DeviceItem device, Item i, string placeholderName, ID renderingId)
        {
            return i == null
                ? new RenderingReference[0]
                : i.Visualization.GetRenderings(device, false).Where(x => x.Placeholder == placeholderName && x.RenderingID == renderingId);
        }

        private static Item GetDataSourceItem(RenderingReference reference)
        {
            return reference != null
                ? GetDataSourceItem(reference.Settings.DataSource, reference.Database)
                : null;
        }

        private static Item GetDataSourceItem(string id, Database db)
        {
            Guid itemId;
            return Guid.TryParse(id, out itemId)
                                    ? db.GetItem(new ID(itemId))
                                    : db.GetItem(id);
        }
        #endregion
    }
}

Some bug fixes applied.