datagrid cell values

Hi I have a DataGridView with a datatable as its datasource. What is the best way to detect that data has been changed by a User? Thanks

Hi dear, Is it possible that I put condition on datagrid cells? i mean if a cell is empty put a specific value in it? coz i'm dealing with a student attendance record and it is very difficult to mark each student absent or present as it is time consuming. So, i want is there any way that if...