public TextFragment(ITextFragmentRepository repo)
 {
     if (_state == null)
     {
         _state      = repo.CreateTextFragmentState();
         _state.Guid = Guid.NewGuid();
         repo.AddTextFragmentState(_state);
     }
 }
 public TextFragment(ITextFragmentRepository repo, ITextFragmentState state) : this(repo)
 {
     _state = state;
 }