Processes all outstanding events without blocking
for user input.
Example
This
procedure counts to 1,000 until you choose STOP:
r-proevs.p
DEFINE VARIABLE ix AS INTEGER NO-UNDO.
DEFINE VARIABLE stop-sel AS LOGICAL NO-UNDO.
DEFINE BUTTON stop-it LABEL "STOP".
DISPLAY stop-it.
ON CHOOSE OF stop-it
stop-sel = TRUE.
ENABLE stop-it.
DO ix = 1 TO 1000:
DISPLAY ix VIEW-AS TEXT.
PROCESS EVENTS.
IF stop-sel THEN LEAVE.
END.
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On each pass through the loop, the procedure
displays the new value of ix and then checks whether
any events are waiting to be processed. If no events have occurred,
execution continues and the loop iterates. If the STOP button has
been chosen, that event is processed changing the value of stop-sel.
When execution continues, the program exits the loop.
If the
loop does not contain the PROCESS EVENTS statement, the choose event
never processes and the loop iterates until ix equals 1,000.
Notes
- The
WAIT-FOR statement processes all pending events and blocks all other
execution until a specified event occurs. The PROCESS EVENTS statement
processes all pending events and immediately continues execution
with the next statement.
- If there are any asynchronous requests for which PROCEDURE-COMPLETE
events have been received but not yet processed, this statement
processes these events as described for the WAIT-FOR statement.
- You cannot call the .NET method system.Windows.Forms.Application:DoEvent( )
in ABL. The PROCESS EVENTS statement performs the function of this
method.
- .NET can raise exceptions in the context of an ABL session
when this statement executes.
- In the context of the .NET blocking method, System.Windows.Forms.Application:Run( ),
if you directly or indirectly execute the PROCESS EVENTS statement
while displaying a non-modal ABL window, in certain contexts (such
as within a user-defined function or non-VOID method)
this statement execution raises the STOP condition. For more information
on the .NET Application:Run( ), method,
see the reference entry for the WAIT-FOR statement (.NET and ABL).
