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