private void chon_Click(object sender, EventArgs e) { Button b = sender as Button; var pr = b.Parent; var num = pr.Controls.Find("SL", false).First() as NumericUpDown; if (num.Value > 0) { Detail.AddOrUpdateDetail(Convert.ToInt32(b.Tag.ToString()), ID_Bill, Convert.ToInt32(num.Value)); pr.BackColor = Color.Yellow; dataGridView1.DataSource = Bill.GetBill(ID_Bill); dataGridView1.Columns["Price"].DefaultCellStyle.Format = "#,##0"; dataGridView1.Columns["Total"].DefaultCellStyle.Format = "#,##0"; textBox2.Text = string.Format("{0:#,##0}", Bill.TotalByBill(ID_Bill)); } }