If I want to log all the changes that are made to a row in the dataset before it is saved, is there a way to know which columns changed within the changed rows?

If I start with a DataTable that is to be saved, I can get the rows that have changes with GetChanges() but then looping through those, is there a way to tell which columns were changed?

Alternatively, is there a way to take a snapshot of a DataSet easily for comparison later?
Thanks
Tim