can you use IEnumerable and IDictionayEnumerator together?

Question

So I just had a question on a practice exam for the 70-536. It goes like this, "you are creating a new collection type for an application the collection type must be iterated through using a foreach loop. Which two interfaces should you use?" - before seeing the answer my first thought was IEnumerable and IEnumerator but it turns out that I didn't even have IEnumerator as an option. Long story short - the answer they say is correct is "IDictionaryEnumerator" and "IEnumerable" - assuming that is right can anyone point to an example of where or when I would combine these two?

 

Thanks!

Answer 1

IDictionaryEnumerator and IEnumerable are clearly correct if there was some mention about there being keys and values.  Although you say it wasn't listed, stating all three: IDictionaryEnumerator, IEnumerable, and IEnumerator is reasonable: whenever you implement IDictionaryEnumerator, you automatically implement IEnumerator as well.

However, if there is no discussion about keys and values, I would consider that practice question suspect.

Answer 2

I'd like to see the exact question because the only reason to use IDictionaryEnumerator is when creating an enumerator for a key/value pair collection.

Answer 3

Hi rok3t,

   Welcome to MSDN forums! I'm glad to see your active participation and discussion in MSDN forums. As far as we konw IDictionayEnumerator was implememts IEnumerator please refer to

    http://msdn.microsoft.com/en-us/library/system.collections.idictionaryenumerator.aspx 

    http://msdn.microsoft.com/en-us/library/system.collections.ienumerable.aspx 

   Hope this will help you!  

   If you still have any doubt and concern about this issue, please let me know. If I misunderstood you, please kindly elaborate your question.

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Best Regards,
Yan Jun
Microsoft Online Community Support