Using system handles in OCX event procedures
- Last Updated: January 17, 2024
- 1 minute read
- OpenEdge
- Version 12.8
- Documentation
ABL allows you to obtain the identities of both the
ActiveX control that generates an event and the associated control-frame
widget from within an OCX event procedure. The COM-SELF system handle
returns the component handle of the ActiveX control and the SELF system
handle returns the widget handle of the control-frame. This is especially
useful in generic event procedures where the source of an event
cannot be known.
Unlike for ABL ON triggers, the RETURN NO-APPLY statement
has no affect in an OCX event procedure. Some COM object events
provide a similar mechanism using output parameters. For example,
the standard KeyPress event passes a key code as an INPUT-OUTPUT parameter.
If you set this parameter to 0 in the event handler, the key is discarded.
APPLY statement. However, to trigger an
ActiveX control event in ABL, you execute its OCX event procedure
as a standard internal procedure, passing any required parameters.