switch (e.Action)
                {
                    case NotifyCollectionChangedAction.Add:
                        entity.AddRange(e.NewItems.Cast<TEntity>());
                        break;
                    case NotifyCollectionChangedAction.Remove:
                        entity.RemoveRange(e.OldItems.Cast<TEntity>());
                        break;
                }

            using (var trans = context.Database.BeginTransaction())
            {
                int pID = (trans.UnderlyingTransaction.Connection as Npgsql.NpgsqlConnection).ProcessID;
                context.SaveChanges();
                trans.Commit();
            }