UNBINDEVENTS( ) Function
You can use UNBINDEVENTS( ) to unbind, or detach, an event that was originally bound to a Visual FoxPro object using BINDEVENT( ). To detach events from Component Object Model (COM) objects, use the EVENTHANDLER( ) function. There are three versions of the syntax.
UNBINDEVENTS(oEventSource, cEvent, oEventHandler, cDelegate)
UNBINDEVENTS(oEventObject)
UNBINDEVENTS(hWnd [, nMessage])
Parameters
- oEventSource
Specifies the event source, which must be a valid Visual FoxPro object.
- oEventObject
Specifies an object reference, which can be used as the event source or event handler.
- cEvent
Specifies the name of the event, method, or property you want to unbind.
- oEventHandler
Specifies the object that is handling the event.
- cDelegate
Specifies the delegate method handling the event for oEventHandler.
hWnd
Specifies the integer handle of the window for which events are unbound.If hWnd is 0, all hWnds are unbound.
If the nMessage parameter isn't included, then all Windows message bindings for the window handle hWnd are unbound.
- nMessage
Specifies a valid Windows message (Win Msg) that is unbound. See MSDN (the Microsoft Developer Network) for information about Windows messages.
Return Value
Numeric data type. UNBINDEVENTS( ) returns the number of events that are unbound if unbinding succeeds. UNBINDEVENTS( ) returns a value of 0 if no events exist for unbinding. Visual FoxPro generates an error if UNBINDEVENTS( ) fails to unbind events that are available for unbinding.
Remarks
The following table describes the ways you can use UNBINDEVENTS( ).
| Syntax | Action |
|---|---|
|
Unbinds a specific event from an event handler. |
|
Unbinds all events associated with this object. This includes events that are bound to it as an event source and its delegate methods that serve as event handlers. |
|
Unbinds all or specific Windows Message (Win Msg) events. |
If an event is occurring, and UNBINDEVENTS( ) or the delegate method handling the event is called, the event and its delegate method finish running before UNBINDEVENTS( ) unbinds the event.
You can call the AEVENTS( ) function retrieve information about all the events and delegate methods attached to a particular object.
Example
The following example shows how to undo a BINDEVENTS( ) call that keeps the Class Browser positioned to the right side of the Visual FoxPro desktop, regardless of how the desktop is resized. UNBINDEVENTS( ) detaches the Resize event of the _SCREEN system variable from the object, oHandler:
PUBLIC oHandler
oHandler=NEWOBJECT("myhandler")
DO (_browser)
BINDEVENT(_SCREEN,"Resize",oHandler,"myresize")
UNBINDEVENTS(_SCREEN,"Resize",oHandler,"myresize")
DEFINE CLASS myhandler AS Session
PROCEDURE myresize
_obrowser.left = _SCREEN.Width - _obrowser.width
RETURN
ENDDEFINE
See Also
Reference
AEVENTS( ) Function
BINDEVENT( ) Function
EVENTHANDLER( ) Function
RAISEEVENT( ) Function
SYS(2325) - WCLIENTWINDOW from Visual FoxPro WHANDLE
SYS(2326) - WHANDLE from a Window's hWnd
SYS(2327) - Window's hWnd from Visual FoxPro WHANDLE
Concepts
Event Binding for Visual FoxPro Objects