Entity Framework Guid

private Guid _identifier = Guid.NewGuid();

void OgaraEntities_SavingChanges(object sender, EventArgs e)
{
  foreach (ObjectStateEntry entry in
      ((ObjectContext)sender).ObjectStateManager.GetObjectStateEntries(
      EntityState.Added ))
  {
    if (!entry.IsRelationship){
      string keyFieldName = entry.EntitySet.ElementType.KeyMembers[0].Name;
      object entity = entry.Entity;
      PropertyInfo pi = entity.GetType().GetProperty(keyFieldName);
      pi.SetValue(entity, Guid.NewGuid(), null);
    }
  }
}