void gvPurchasingDetail_FocusedRowObjectChanged(object sender, DevExpress.XtraGrid.Views.Base.FocusedRowObjectChangedEventArgs e)
        {
            GridView View = sender as GridView;

            if (View.FocusedColumn.FieldName == "SerialNumber" && !this.SelectedPurchasingDetail.IsSpecialSparepart)
            {
                object fieldSerialNumber = View.GetFocusedRowCellValue(View.FocusedColumn.FieldName);
                if (fieldSerialNumber != null)
                {
                    string serialNumber = fieldSerialNumber.ToString();

                    if (!_presenter.ValidateSerialNumber(serialNumber))
                    {
                        this.ShowWarning("Nomor seri " + serialNumber + " sudah digunakan.");
                    }
                }
            }
        }