I have a need to use certain methods in the System.IO Namespace from an Excel VBA macro (Specifically, methods and properties in the Path class). What I can't figure out, is what reference to add to be able to use this class.

Can anyone point me in the right direction? Note that I am interested in this question for two reasons:

1. How to do this specifically (that is, how use Path.GetRandomFileName, e.g. from VBA)
2. How to do this generally (to be able to reference other .Net objects)