private void BTN_SAVE_Click(object sender, EventArgs e)
 {
     if (DGV_ITEMS_LIST.Rows.Count == 0)
     {
         TXT_ITEMNAME.Focus();
         MSGBOX mdg = new MSGBOX(MessageAlertHeder.Alert(), "PLEASE ADD ITEMS FIRST!", MessageAlertImage.Alert());
         mdg.ShowDialog();
     }
     else if (CMB_SUPPLIER.SelectedIndex == -1)
     {
         CMB_SUPPLIER.Focus();
         MSGBOX mdg = new MSGBOX(MessageAlertHeder.Alert(), "PLEASE SELECT SUPPLIER!", MessageAlertImage.Alert());
         mdg.ShowDialog();
     }
     else if (Convert.ToDouble(TXT_CARD.Text) <= 0 && TXT_CARD_NO.Text == string.Empty)
     {
         TXT_CARD_NO.Focus();
         MSGBOX mdg = new MSGBOX(MessageAlertHeder.Alert(), "PLEASE ENTER CARD NO!", MessageAlertImage.Alert());
         mdg.ShowDialog();
     }
     else if (Convert.ToDouble(TXT_CHEQUE.Text) > 0 && (TXT_CHEQUE_NO.Text == string.Empty || CMB_CHEQUE_BANK.SelectedIndex == -1))
     {
         TXT_CHEQUE_NO.Focus();
         MSGBOX mdg = new MSGBOX(MessageAlertHeder.Alert(), "PLEASE ENTER CHEQUE INFORMATIONS!", MessageAlertImage.Alert());
         mdg.ShowDialog();
     }
     else
     {
         SAVEGRN();
     }
 }
 private void TXT_CHEQUE_NO_KeyDown(object sender, KeyEventArgs e)
 {
     if (e.KeyCode == Keys.Enter)
     {
         TXT_CARD_NO.Focus();
     }
 }