Hi
I test you code it execute without error.
Please attend to bellow point:
1)This code is OK.
dataGridView1.CurrentRow.Cells[YourColumnNumber].Value = DateTime.Now;
2)The first column number is zero, therefore if you want add date to third column you must use from 2 az YourColumnNumber
3)You can use from upper code in Button_Click
I hope it's helpful