How to get next row data?

Hey everybody,
In the selectRow event i got 3 params: (e, row, rowIndex).

in this function the row param is the **data** of the current row selected.
I need to get the **data** of the **next/prev** row.

I can't use the rowIndex, cause i didnt find a way to get the data for a row by it's index.
how can i do it? please help me..

thanks a lot,
Tommy