inline QPersistentModelIndex persistentIndex() const { return _index; }
inline const MessageModel *model() const { return _index.isValid() ? qobject_cast<const MessageModel *>(_index.model()) : 0; }
inline int row() const { return _index.isValid() ? _index.row() : 0; }
inline QPersistentModelIndex persistentIndex() const { return _index; }
inline const MessageModel *model() const { return _index.isValid() ? qobject_cast<const MessageModel *>(_index.model()) : 0; }
inline int row() const { return _index.isValid() ? _index.row() : 0; }