View Source wxCloseEvent (wx v2.4.2)
Functions for wxCloseEvent class
This event class contains information about window and session close events.
The handler function for EVT_CLOSE is called when the user has tried to close a
a frame or dialog box using the window manager (X) or system menu (Windows). It
can also be invoked by the application itself programmatically, for example by
calling the wxWindow:close/2
function.
You should check whether the application is forcing the deletion of the window
using canVeto/1
. If this is false, you must
destroy the window using
wxWindow:'Destroy'/1
.
If the return value is true, it is up to you whether you respond by destroying the window.
If you don't destroy the window, you should call veto/2
to let the calling
code know that you did not destroy the window. This allows the
wxWindow:close/2
function to return true or false depending on whether the
close instruction was honoured or not.
Example of a wxCloseEvent
handler:
The EVT_END_SESSION event is slightly different as it is sent by the system when
the user session is ending (e.g. because of log out or shutdown) and so all
windows are being forcefully closed. At least under MSW, after the handler for
this event is executed the program is simply killed by the system. Because of
this, the default handler for this event provided by wxWidgets calls all the
usual cleanup code (including wxApp::OnExit()
(not implemented in wx)) so that
it could still be executed and exit()s the process itself, without waiting for
being killed. If this behaviour is for some reason undesirable, make sure that
you define a handler for this event in your wxApp-derived class and do not call
event.Skip()
in it (but be aware that the system will still kill your
application).
See: wxWindow:close/2
,
Overview windowdeletion
This class is derived (and can use functions) from: wxEvent
wxWidgets docs: wxCloseEvent
Events
Use wxEvtHandler:connect/3
with wxCloseEventType
to subscribe to events of this type.
Summary
Functions
Returns true if you can veto a system shutdown or a window close event.
Returns true if the user is just logging off or false if the system is shutting down.
Sets the 'can veto' flag.
Sets the 'logging off' flag.
Call this from your event handler to veto a system shutdown or to signal to the calling application that a window close did not happen.
Types
-type wxClose() :: #wxClose{type :: wxCloseEvent:wxCloseEventType()}.
-type wxCloseEvent() :: wx:wx_object().
-type wxCloseEventType() :: close_window | end_session | query_end_session.
Functions
-spec canVeto(This) -> boolean() when This :: wxCloseEvent().
Returns true if you can veto a system shutdown or a window close event.
Vetoing a window close event is not possible if the calling code wishes to force the application to exit, and so this function must be called to check this.
-spec getLoggingOff(This) -> boolean() when This :: wxCloseEvent().
Returns true if the user is just logging off or false if the system is shutting down.
This method can only be called for end session and query end session events, it doesn't make sense for close window event.
-spec setCanVeto(This, CanVeto) -> ok when This :: wxCloseEvent(), CanVeto :: boolean().
Sets the 'can veto' flag.
-spec setLoggingOff(This, LoggingOff) -> ok when This :: wxCloseEvent(), LoggingOff :: boolean().
Sets the 'logging off' flag.
-spec veto(This) -> ok when This :: wxCloseEvent().
-spec veto(This, [Option]) -> ok when This :: wxCloseEvent(), Option :: {veto, boolean()}.
Call this from your event handler to veto a system shutdown or to signal to the calling application that a window close did not happen.
You can only veto a shutdown if canVeto/1
returns true.