check if row has data in gridview and add new rows

Hi,
I am using C#.
I have a datatable which has 3 columns (FirstName , MiddleName, LastName ). I have a gridview, which i have bound to the datatable.
Initially i have kept one empty row in the datatable and binded it to gridview. I want to insert a new data to the datatable, however, I would like to check if the existing row has any data in it, If there is a data in the rows, then create a new row and insert the new item. How to achieve this?
Thanks