public IEnumerable <Prr> GetPrrs(Wrr wrr) { wrr.StdfFile.GetRecordsEnumerable().Any(); //find the part extents within the wafer extent var waferExtent = _WafersMap.GetExtents(wrr); return(from pe in _PartsMap.GetExtentsListWithin(waferExtent) from prr in GetRecordsInExtentsReverse(pe) .TakeWhile(r => r.GetType() == typeof(Prr)) .Select(r => (Prr)r) select prr); }