Bind, Raise, Unbind, and Retrieve Events Sample
File: ...\Samples\Solution\Toledo\FrmEvents.scx
This sample demonstrates binding events, raising events programmatically, unbinding events, and retrieving events for _SCREEN system variable, or the main Visual FoxPro window. In the sample, you can manually raise a bound event for _SCREEN by selecting an event from the combo box or invoke the same events and their respective handlers by using the mouse.
For more information about _SCREEN, see _SCREEN System Variable.
Binding Events
To respond to Visual FoxPro events, use the BINDEVENT( ) function. In this sample, the BINDEVENT( ) function is called in the custom InitBindEvent method and binds several _SCREEN events to the form's methods. When one of the _SCREEN events fires, the associated handler method is called:
BINDEVENT(_SCREEN,"Resize",ThisForm,"screenresize")
BINDEVENT(_SCREEN,"Mousedown",ThisForm,"screenmousedown")
BINDEVENT(_SCREEN,"Mouseup",ThisForm,"screenmouseup")
BINDEVENT(_SCREEN,"Rightclick",ThisForm,"screenrightclick")
BINDEVENT(_SCREEN,"Dblclick",ThisForm,"screendblclick")
For more information, see BINDEVENT() Function and Init Event.
Raising Events Programmatically
To raise events programmatically, use the RAISEEVENT( ) function. In this sample, when the combo box is selected, the InteractiveChange event uses the returned value to programmatically raise the specified event.
RAISEEVENT(_SCREEN,this.Value)
For more information, see RAISEEVENT() Function and InteractiveChange Event.
Unbinding Events
To unbind event handlers, use the UNBINDEVENTS( ) function. In this sample, the custom UnbindHandlers method unbinds events for _SCREEN.
UNBINDEVENTS(_SCREEN)
For more information, see UNBINDEVENTS() Function.
Retrieve Event Bindings
To retrieve existing event bindings into an array, use the AEVENTS( ) function. In this sample, the custom ScreenDblClick method, which is bound to the _SCREEN DblClick event, uses the AEVENTS( ) function to report the number of event bindings:
AEVENTS(laEvents,Thisform)
For more information, see AEVENTS() Function, and DblClick Event.
See Also
Concepts
Event Binding for Visual FoxPro Objects