I am developing applications in Application Express 4.2.3.00.08. I defined a page item :P8_CONTACT_RESULT_IND with the following properties.
List of Values
Display Extra Values: Yes
Display Null Values: Yes
Display Null Value: - Select -
List of Values Definition: STATIC2:Successful;Y,Left Messages;M,Busy;B,No Answer;N,Wrong Number;W
Source
Source Used: Always, replacing any existing value in session state
Source Type: Database column
Source value or expression: CONTACT_RESULT_IND
Everything was working fine but the user made some changes to the requirements. One of the new requirements is that whatever the value for CONTACT_RESULT_IND in the current row the List of Values should display null, that is - Select -. I created a post calculation computation to return null as follows:
Post calculation computation: SUBSTR(:P8_CONTACT_RESULT_IND,1,-1)
The page item still displays the value based the data in CONTACT_RESULT_IND, e.g. if it is set to ‘M’ the page item displays ‘Left Messages.’ I confirmed the SUBSTR function is executed because if I change the function to SUBSTR(:P8_CONTACT_RESULT_IND || ‘B’,2,1) then ‘Busy’ displays even though the data value is ‘M.’
How do I force this page item to display a null regardless of the value of the underlying database column?