private void barcodeSerial_KeyDown(object sender, KeyEventArgs e)
        {
            int quan = 0;

            if (e.Key == Key.Enter && barcodeSerial.Text != "")
            {
                if (IsAlreadyExists(barcodeSerial.Text) == true)
                {
                    Xceed.Wpf.Toolkit.MessageBox.Show("The barcode is already in the list. Pres ok to exit.", "Duplicate Barcode", MessageBoxButton.OK, MessageBoxImage.Error, MessageBoxResult.OK);
                    barcodeSerial.Clear();
                    return;
                }
                else if (ProductTableData.hasBarcodeinDB(barcodeSerial.Text) == true)
                {
                    Xceed.Wpf.Toolkit.MessageBox.Show("The barcode is already in the Database. Pres ok to exit.", "Duplicate Barcode in DB", MessageBoxButton.OK, MessageBoxImage.Error, MessageBoxResult.OK);
                    barcodeSerial.Clear();
                    return;
                }
                else if (sameBarcode.IsChecked == true && listView.Items.Count >= 1)
                {
                    Xceed.Wpf.Toolkit.MessageBox.Show("You can add only one barcode. Pres ok to exit.", "Barcode", MessageBoxButton.OK, MessageBoxImage.Error, MessageBoxResult.OK);
                    barcodeSerial.Clear();
                    return;
                }
                else if (uniqBarcode.IsChecked == true && int.TryParse(quantity.Text, out quan) == true && listView.Items.Count > quan - 1)
                {
                    Xceed.Wpf.Toolkit.MessageBox.Show("You cannot add barcode more than quantity. Press ok to exit.", "Barcode", MessageBoxButton.OK, MessageBoxImage.Error, MessageBoxResult.OK);
                    barcodeSerial.Clear();
                    return;
                }
                listView.Items.Add(new ListViewItems(listView.Items.Count + 1, barcodeSerial.Text, "NONE"));
                listView.SelectedIndex = listView.Items.Count - 1;
                listView.ScrollIntoView(listView.SelectedItem);
                barcodeSerial.Clear();
            }

            if (e.Key == Key.Enter && quan == listView.Items.Count && product.Unique_Barcode.StartsWith("Y"))
            {
                var uie = e.OriginalSource as UIElement;
                e.Handled = true;
                uie.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
            }
        }