How do I save an index to a particular index of a dropdownlist in a datagrid.

[macsgirl]

Say I have mutliple dropdownlist in my datagrid.
and I want to keep the index when I make a modification to a specific dropdownlist.
that is the dropdownlist for instance started at country Canada but I modified it to USA. I want it
to stay at USA. Do I have to create a separate function to save the index of each dropdownlist in editmode. If not how do I approach this