Set Focus In Datagridview:C#

Question

Hi,
My datagridview contains 3 columns, I have displayed values in these cells on the cell enter event, if the user do not enter any value in any of three cells, the new row is not added. The new row only get added if the value in written in any of the cell. So, what can i do to add a new row on the cell leave event of the last cell.
Thanks,
Vidya