CollectionBase no IList implementation?

Question

Would anyone explain to me why in the abstract CollectionBase class (in System.Collections which derives from IList) it does not have the IList members implemented? I thought it was obligatory.

Answer 1

It implements IList explicitly, so you'll need to cast your CollectionBase instance to IList to access those members.

IList list = (IList)collectionBase;
list.Add(...);