SystemError event
Description
Occurs when a serious runtime error occurs (such as trying
to open a nonexistent window) if the error is not handled in a try-catch
block.
Event ID
|
Event ID |
Objects |
|---|---|
|
None |
Application |
Parameters
None
Return Values
None. (Do not use a RETURN statement.)
Usage
If there is no script for the SystemError event, PowerBuilder
displays a message box with the PowerBuilder error number and error
message text. For information about error messages, see the PowerBuilder
Users Guide.
If you comment out the entire script in the SystemError event,
a Windows Forms application behaves as if there is no script for
the event and the message box displays, but in a standard PowerBuilder
application the event is still triggered and the message box does
not display.
For errors involving external objects and DataWindows, you
can handle the error in the ExternalException or Error events and
prevent the SystemError event from occurring. The ExternalException
and Error events are maintained for backward compatibility.
You can prevent the SystemError event from occurring by handling
errors in try-catch blocks. Well-designed exception-handling code
gives application users a better chance to recover from error conditions
and run the application without interruption. For information about
exception handling, see Application Techniques.
When a SystemError event occurs, your current script terminates
and your system might become unstable. It is generally not a good
idea to continue running the application, but you can use the SystemError
event script to clean up and disconnect from the DBMS before closing
the application.
Examples
This statement in the SystemError event halts the
application immediately:
|
1 |
HALT CLOSE |