sir, the above code
"Cells[1],Cells[8]" are used to get data from the datagridview. let me give you another simple example for this:-
datagridview1.SelectedRows["Col_Name"].Text;
datagridview1.SelectedRows[1].Text;
both of the above line does the same work and
"Cells[1],Cells[8]" in the above context means that you are trying to access cells of current focused column of datagridview at position 2 and 8.