it can be many ways to achive the above requirment.
as you said u need to edit some of the cells(column) in the girdview..
1. You need to convert those bound column to template columns & define the edit template
2. Add the Edit Button Column
3. In RowEditing Event .. change the gridview editindex to e.neweditindex
4. In RowUpdating Event get new values & update the database.
5. Bind the gridview again
Hope it helps