Hello friends,
 
I m using code for barcode saccning . i m reteriving data from database when text box fill by accession no but i dont have any idea which event should i used for it.. if do you have any idea then plz reply me ASAP..
 
 
  private void stock_verification()
        {
            Boolean found = false;
            foreach (DataGridViewRow row in gv_show_details.Rows)
            {
                if (row.Cells[0].Value.ToString() == txt_accession_no.Text)
                {
                    found = true;
                    MessageBox.Show("Book already exists", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    txt_accession_no.Text = "";
                    txt_accession_no.Focus();
                    break;
                }
            }
            if (!found)
            {
                try
                {
                    MySqlConnection con = new MySqlConnection(StartUp.database);
                    con.Open();
                    MySqlCommand cmd = new MySqlCommand("call ps_stock_verification_books('" + txt_accession_no.Text + "')", con);
                    MySqlDataReader dr = cmd.ExecuteReader();
                    if (dr.HasRows)
                    {
                        dr.Read();
                        gv_show_details.Rows.Add();
                        gv_show_details.Rows[i].Cells[0].Value = dr[0].ToString();
                        gv_show_details.Rows[i].Cells[1].Value = dr[1].ToString();
                        gv_show_details.Rows[i].Cells[2].Value = dr[2].ToString();
                        gv_show_details.Rows[i].Cells[3].Value = dr[3].ToString();
                        gv_show_details.Rows[i].Cells[4].Value = dr[4].ToString();
                        gv_show_details.Rows[i].Cells[5].Value = dr[5].ToString();
                        gv_show_details.Rows[i].Cells[6].Value = dr[6].ToString();
                        i++;
                    }
                    lbl_number_of_bboks.Text = "Number of Books : " + gv_show_details.RowCount;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
        } 
 
private void txt_accession_no_Validating(object sender, CancelEventArgs e)
        {
            stock_verification();
            txt_accession_no.Focus();
            txt_accession_no.Text = "";
        }