Example for http://stackoverflow.com/q/15904351/1077279

Program.cs

using System;
using System.Linq;
using DevExpress.Xpo;
using DevExpress.Xpo.DB;

namespace XpoConsoleApplication1
{
    class Program
    {
        public class Photo : XPObject
        {
            public Photo(Session session)
                : base(session)
            { }

            private string _Description;
            public string Description
            {
                get
                { return _Description; }
                set
                { SetPropertyValue("Description", ref _Description, value); }
            }
        }

        static void Main(string[] args)
        {
            XpoDefault.DataLayer = new SimpleDataLayer(new InMemoryDataStore());
            using (UnitOfWork uow = new UnitOfWork())
            {
                var photo = new Photo(uow);
                photo.Description = "Something";
                // create a new photo and save it
                uow.CommitChanges();
                if (photo.Description != "Something")
                    throw new Exception("This should not happen");
            }

            using (UnitOfWork uow = new UnitOfWork())
            {
                var photos = new XPCollection<Photo>(uow);
                photos[0].Description = "Something new";
                uow.CommitTransaction();
                if (photos[0].Description != "Something new")
                    throw new Exception("This should not happen");
            }

            Console.WriteLine("All ok");
            Console.ReadKey();
        }
    }
}