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comp.lang.ruby

Intercepting events with wxRuby/wxWidgets

Rainer

1/6/2008 6:19:00 PM


Hello everybody,

I have a question concerning wxRuby/wxWidgets. I'm getting my feet wet
with a simple application that holds one Wx::Frame called VwX.

When my application gets closed, I want the user to decide whether the
app really will shut down. If it shuts down: Save the last changes or
not? Typical Yes/No/Cancel situation. So I do this: (Remark:
VwXEvOnClose(event) is the "on_close" event of my Wx::Frame):

def VwXEvOnClose(event)
dlg = MessageDialog.new(nil, "Save changes?", "MyApp",
Wx::YES_DEFAULT|Wx::CANCEL|Wx::YES_NO|Wx::ICON_EXCLAMATION)
command = dlg.show_modal
dlg.destroy

case command
when Wx::ID_CANCEL
event.veto

when Wx::ID_YES
save_my_changes
event.skip

else
event.skip
end
end

This works as it is supposed to. However, I noticed that the call to
"event.veto" might just as well be missing without any problems. OTOH,
the calls to "event.skip" are essential: If I dont call these, the
application simply won't shut down. Any ideas why the veto is
unimportant?
3 Answers

Alec Ross

1/6/2008 8:26:00 PM

0

In message
<50925ed1-4211-4405-b6aa-0e73f896b227@e4g2000hsg.googlegroups.com>,
Rainer <wolf.rainer@gmail.com> writes
>
>Hello everybody,
>
>I have a question concerning wxRuby/wxWidgets. I'm getting my feet wet
>with a simple application that holds one Wx::Frame called VwX.
>
....

wxruby-users is a good place to post this kind of question.

HTH

Alec
--
Alec Ross

Alex Fenton

1/6/2008 9:17:00 PM

0

Rainer wrote:
> Hello everybody,
>
> I have a question concerning wxRuby/wxWidgets. I'm getting my feet wet
> with a simple application that holds one Wx::Frame called VwX.

As noted, wxruby-users is a better place to ask questions specifically
about wxRuby.

> When my application gets closed, I want the user to decide whether the
> app really will shut down. If it shuts down: Save the last changes or
> not? Typical Yes/No/Cancel situation. So I do this: (Remark:
> VwXEvOnClose(event) is the "on_close" event of my Wx::Frame):

....

> This works as it is supposed to. However, I noticed that the call to
> "event.veto" might just as well be missing without any problems. OTOH,
> the calls to "event.skip" are essential: If I dont call these, the
> application simply won't shut down. Any ideas why the veto is
> unimportant?

The veto method only applies to close events; the documentation explains
that:

"If you don't destroy the window, you should call Wx::CloseEvent#veto to
let the calling code know that you did not destroy the window. This
allows the Wx::Window#close function to return true or false depending
on whether the close instruction was honoured or not."

hth
alex

Rainer

1/6/2008 10:14:00 PM

0

On 6 Jan., 22:16, Alex Fenton <a...@deleteme.pressure.to> wrote:

> The veto method only applies to close events; the documentation explains
> that:
>
> "If you don't destroy the window, you should call Wx::CloseEvent#veto to
> let the calling code know that you did not destroy the window. This
> allows the Wx::Window#close function to return true or false depending
> on whether the close instruction was honoured or not."
>
> hth
> alex

Hello Alex,

this sounds like the method doesn't actually perform the veto, it just
informs the calling code that the window wasn't destroyed. Makes
sense, thank you. I only read the "short" documentation which states:

"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 wxCloseEvent::CanVeto returns true."

This sounded to me that there are cases when you actually perform the
veto. Case closed anyway: I will leave the method call in, of course.

Alec, thank you, too, for the hint with the wxruby-users mailing list.
I will reserve this for the harder cases, though, as this newsgroup
was absolutely fit for the task!

Thanks everybody,

Rainer