Release 10.1A: OpenEdge Development:
Progress Dynamics Advanced Development

Writing the supporting procedures for the UI event

Now you must edit the customersuper.p procedure to add the internal procedure to be executed when the UI event occurs so that CreditLimitLeave checks first to see if the CreditLimit field has been modified. First create a support function, called widgetModified, to take care of that check. This function checks the Progress 4GL MODIFIED attribute for the field and returns true or false accordingly, as shown:

FUNCTION widgetModified RETURNS LOGICAL ( pcField AS CHARACTER ) : /*------------------------------------------------------------------------- Purpose: Returns TRUE if the widget value has been changed. Params: pcField AS CHARACTER -------------------------------------------------------------------------*/ DEFINE VARIABLE hField AS HANDLE NO-UNDO. hField = widgetHandle(pcField). IF VALID-HANDLE(hField) AND CAN-SET (hField, 'MODIFIED') AND hField:MODIFIED THEN RETURN TRUE. ELSE RETURN FALSE. END FUNCTION.

The next step is to code the CreditLimitLeave procedure itself. In this example, the same condition is duplicated from the rowDisplay procedure. Obviously, in a properly completed example this code should be pulled out into a separate internal procedure called from both places, as shown:

PROCEDURE CreditLimitLeave: /*------------------------------------------------------------------------- Purpose: Check the CreditLimit against the balance on LEAVE. Parameters: <none> -------------------------------------------------------------------------*/ IF widgetModified('CreditLimit') THEN IF DECIMAL(widgetValue('CreditLimit')) - DECIMAL(widgetValue('Balance')) < 5000 THEN highlightWidget('Balance'). ELSE unhighlightWidget('Balance'). END PROCEDURE.