Show Auto generated Serial No in Data Grid Column in WPF

Question

I have my data grid view in WPF.I bound  all the data from my datatable to my datagrid view.But now i want the Serial No column to my data grid view .

"S.No" IsReadOnly="True" Width="40" />

By this code i insert the column in my datagrid view.I need to auto generate the serial No. please help me to solve this problem.Any help will be appreciated.