public void Normalize()
 {
     this.BillCode    = BillCode?.Trim();
     this.RangeBegin  = RangeBegin?.DateBegin();
     this.RangeEnd    = RangeEnd?.DateEnd();
     this.OrderNumber = OrderNumber?.Trim().ToUpper();
     this.ItemNumber  = ItemNumber?.Trim().ToUpper();
 }