private void comboBox1_SelectionChangeCommitted(object sender, EventArgs e) { if (Convert.ToInt32(comboBox1.SelectedValue) > 0) { string _date = lc.getsubmissiondate(Convert.ToInt32(dataGridView1.SelectedCells[0].Value), Convert.ToInt32(comboBox1.SelectedValue)); DateTime d1 = Convert.ToDateTime(_date); double ans = lc.forFine(d1); if (ans > 0) { submissiondatetb.BackColor = Color.Red; submissiondatetb.Text = d1.ToShortDateString().ToString(); days = Convert.ToInt32(ans); fine = lc.calculateFine(days); } else { submissiondatetb.BackColor = Color.LightGreen; submissiondatetb.Text = d1.ToShortDateString().ToString(); } } }