text: public virtual string DistanceSubQueryNotAllowed(){var sqi = GetSubQueriesEnumerator();while (sqi.MoveNext()){var leq = sqi.Current;if (leq is IDistanceSubQuery){var dsq = sqi.Current as IDistanceSubQuery;string m = dsq.DistanceSubQueryNotAllowed();if (m != null){return m;}}else{return "Operator " + OperatorName + " does not allow subquery " + leq.ToString();}}return null; }