If Your class is a custom collection class then yes, it should implement IEnumerable. In this case a public property for the inner list would be redundant. Imagine a simple class: Birey a unique position be deduced if pieces are replaced by checkers (can see piece color but hamiş type) https://cesariwflv.wikiconverse.com/4846187/büyülenme_hakkında_c_ienumerable_temel_Özellikleri