保存或更新后的FindAll不返回更新

代码概要:

public void UpdateRecords(long aParentId)
{
   IList<Parent> parents = parentRepository.GetParentById(aParentId);
   foreach (Parent parent in parents)
   {
      Child childToUpdate = childRepository.GetChildById(parent.GetChildId());

      ... Update Child ...

      childRepository.SaveChild(childToUpdate);
   }
   IList<Parent> parents = parentRepository.GetParentById(aParentId);
}

class ParentRepository : NHRepository
{
   public IList<Parent> GetParentById(long anId)
   {
      DetachedCriteria criteria = 
         DetachedCriteria.For<Parent>()
         .Add(Restrictions.Eq("Id", anId));

      return FindAll(criteria).ToList();
   }
}

class ChildRepository : NHRepository
{
   public Child SaveChild(Child aChild)
   {
      Child savedChild = null;
      using (UnitOfWork.Start())
      {
         savedChild = base.SaveOrUpdate(aChild);
         UnitOfWork.Current.Flush(); // commit
      }
      return savedChild;
   }
}