Is there a method to convert a superclass to one of its subclasses?

More specifically: I have a function that returns an Object class There's no way around this -- it has to return an Object. It's actually a generic "List" class used to store any type of data in a list. I don't want to wander too far off course here. Bottom line: It was to be an Object.

I do, however, know that it will only return a CDataSet class, because I'm only using it to store CDataSet objects. How can I 'convert' the returned Object class to a CDataSet object?

(Note: CDataSet is a custom class).

Thanks