code: @Override
      protected String getReadOnlyValue(final AbstractUIField _uiField)
          throws EFapsException
      {
          Object ret = _uiField.getValue().getReadOnlyValue(_uiField.getParent().getMode());
          if (ret instanceof Type) {
              ret = ((Type) ret).getLabel();
          }
          return ret == null ? "" : String.valueOf(ret);
      }
docs: {@inheritDoc}