Kbase P6864: 4GL: How to know if an instance of an OCX is running?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
3/7/2003 |
|
Status: Unverified
GOAL:
4GL: How to know if an instance of an OCX is running?
FACT(s) (Environment):
Progress 9.X
FIX:
Rely on a 4GL SUBSCRIBE + PUBLISH mechanism in each procedure that uses the OCX as illustrated bellow:
1) Define the following variable in the definition block:
DEFINE VARIABLE IsTheOcxRunningFlag AS LOGICAL NO-UNDO.
2) Subscribe to a 'IsTheOcxRunning' event when initializing the ActiveX (such as in Internal Procedure initialize-controls or adm2 initializeObject):
SUBSCRIBE TO "IsTheOcxRunning" ANYWHERE.
3) Make the following Internal Procedure:PROCEDURE IsTheOcxRunning:
/* Will happen when 'IsTheOcxRunning' published by itself */
IF SOURCE-PROCEDURE = THIS-PROCEDURE THEN RETURN.
/* Now we know that 'IsTheOcxRunning' was published by an other procedure */
DYNAMIC-FUNCTION("setIsTheOcxRunning" IN SOURCE-PROCEDURE, INPUT YES).
END PROCEDURE.
4) Collect the answer of the procedure(s) with the following function:FUNCTION setIsTheOcxRunning RETURNS LOGICAL
(INPUT inFlag AS LOGICAL) :
IsTheOcxRunningFlag = inFlag.
RETURN YES. /*Actually, we do not care about this returned value
=> Similar to a method that returns true when the process
was successful */
END FUNCTION.
5) Read the answer of the procedure(s) with the following function:FUNCTION getIsTheOcxRunning RETURNS LOGICAL
( /* parameter-definitions */ ) :
RETURN IsTheOcxRunningFlag. /* Function return value. */
END FUNCTION.
6) Example of use:ON CLOSE OF THIS-PROCEDURE DO:
setIsTheOcxRunning(NO). /*not necessary if we do the job only once before
closing the procedure*/
PUBLISH "IsTheOcxRunning".
IF getIsTheOcxRunning() THEN
MESSAGE "The OCX is running somewhere else, don't release it"
VIEW-AS ALERT-BOX INFO BUTTONS OK.
ELSE MESSAGE "No, the OCX was not used somewhere else" SKIP
"So we can release it"
VIEW-AS ALERT-BOX INFO BUTTONS OK.
RUN disable_UI.
END.