Get all tracked entities from a DbContext?

Question

Many of the tables in my database need to have a \"DateCreated\" and \"DateModified\" column. I want to update these columns whenever SaveChanges() is called.

Answer 1

This has worked well in our project so we don't have to remember to override something every time we add a new entity that has our standard LastUpdatedDateTime property. Using EF4; for an EF5 DbContext I think ((IObjectContextAdapter)_dbContext).ObjectContext.ObjectStateManager would get you the object state manager:

// In our SaveChanges wrapper:
        var entries = context.ObjectStateManager.GetObjectStateEntries(EntityState.Added | EntityState.Modified | EntityState.Deleted);

        private static void PopulateDate(IEnumerable entries)
                {
                    foreach (var entry in entries)
                    {
                        if (entry.State != EntityState.Deleted)
                        {
                            if ((entry.Entity != null) && (entry.Entity.GetType().GetProperty("LastUpdatedDateTime") != null))
                            {
                                ((dynamic)entry.Entity).LastUpdatedDateTime = DateTime.UtcNow;
                            }
                        }
                    }
                }

The reflection call is not an issue: for an object with 25 properties (alot), a million reflection queries takes an avg ~210 ms.