Easier .NET settings

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Practices.Unity;
using Microsoft.Practices.ObjectBuilder2;
using Microsoft.Practices.Unity.ObjectBuilder;

namespace Tracking
{
    /// <summary>
    /// Marker interface for classes that want their tracking to be handled 
    /// by the IOC container.
    /// <remarks>
    /// Checking if a class implements an interface is faster that checking
    /// if its decorated with an attribute.
    /// </remarks>
    /// </summary>
    public interface ITrackable
    {
    }

    /// <summary>
    /// Unity extension for adding (attribute based) state tracking to creted objects
    /// </summary>
    public class TrackingExtension : UnityContainerExtension
    {
        class TrackingStrategy : BuilderStrategy
        {
            IUnityContainer _container;
            public TrackingStrategy(IUnityContainer container)
            {
                _container = container;
            }

            public override void PostBuildUp(IBuilderContext context)
            {
                base.PostBuildUp(context);
                ITrackable autoTracked = context.Existing as ITrackable;
                if (autoTracked != null)
                {
                    List<SettingsTracker> trackers = new List<SettingsTracker>(_container.ResolveAll<SettingsTracker>());
                    if (_container.IsRegistered<SettingsTracker>())
                        trackers.Add(_container.Resolve<SettingsTracker>());

                    foreach (SettingsTracker tracker in trackers)
                    {
                        tracker.Configure(autoTracked).AddMetaData().SetMode(PersistModes.Automatic);
                        tracker.ApplyState(autoTracked);
                    }
                }
            }
        }

        protected override void Initialize()
        {
            Context.Strategies.Add(new TrackingStrategy(Container), UnityBuildStage.Creation);
        }
    }
}