I recently had the need to use the .Net Com interop features to pass a collection from a Microsoft Access VBA application to a VB.Net class. Apparently VBA collections and .Net collections are not compatible because it didn't work at all. So, I did what any decent programmer would do, I Googled it. I found several suggestion, none of which worked completely. I eventually decided to use the method below. It requires that the VBA application pass a Collection object to the .Net class. The .Net class can then work with the collection, and even return it to the VBA application.