public string GetCartInputFieldName( 
   string orderLineID 
)

public void validateOrderLineFieldValues( Order order, int orderStep )
{     
    List<ValidationField> validationFields = ValidationField.GetAllFields(orderStep);
    Dictionary<string, string> errorMsgs = null;
    Report errorReport = new Report(orderStep);
 
    foreach(OrderLine mainOrderLine in order.OrderLines )
    {
        OrderLineCollection orderLinesWithBOM = new OrderLineCollection();
        orderLinesWithBOM.Add(mainOrderLine);
        foreach( OrderLine bomOrderLine in mainOrderLine.BOMOrderLines )
            orderLinesWithBOM.Add(bomOrderLine);

        foreach( OrderLine orderLine in orderLinesWithBOM )
        {
            foreach( OrderLineFieldValue orderLineFieldValue in orderLine.OrderLineFieldValues )
            {
                if( orderLineFieldValue.OrderLineFieldSystemName == validationfield.SystemName )
                {
                    String value = Base.Request(OrderLineFieldValue.GetCartInputFieldName(OrderLine.ID));
                    {
                        if( value == null || !validation.Validates(value) ) 
                        {
                             if( errorMsgs == null ) errorMsgs = settings.GetValidationErrorMsgs();
                             errorReport.Add(validationfield, errorMsgs(validation.ID));
                             orderLineFieldValue.ValidationErrorMessage = errorMsgs(validation.ID);
                        }
                        else {
                            orderLineFieldValue.ValidationErrorMessage = "";
                        }
                        break; // On a single orderline, no two orderlinefields are the same.
                }
            }
        }

        return errorReport;
    }
}