Crystal Report bases of excel file question

I added a crystal report item to my vb.net project and used to wizard to
create a report of an Excel file. I also have a reportviewer on my form and
am able to view the report just fine. What I can't figure out is how to
change which Excel file the report is linked to on the fly from my program.
Can anyone help me with this? I present user a list of Excel files to choose
from. They all have the same format but different rows of data. Shouldn't I
be able to tell the report which excel file to use? All the examples that I
can find are based of ADO datasets connected to the reports.

Thanks!