Цитата:
It is best practice to use the (SetEnumerator) class instead of the SetIterator class. This avoids problems if you are accessing the set on one tier with an iterator on another tier. Set iterators and the sets over which they iterate must be on the same client/server side. If you use SetIterator and code is marked as Called from, it is possible that the set and the iterator will end up on different tiers, and the code will fail. If you use SetEnumerator, the enumerator is automatically created on the same tier as the set. Also, to move to the next item in a set, you must explicitly call the more and next methods if you are using a set iterator. If you use SetEnumerator, you only have to call moveNext method.
https://msdn.microsoft.com/en-us/lib...titerator.aspx