Re: Test for dialog existence
- To: mathgroup at smc.vnet.net
- Subject: [mg112776] Re: Test for dialog existence
- From: David Reiss <dbreiss at gmail.com>
- Date: Thu, 30 Sep 2010 04:50:58 -0400 (EDT)
- References: <i7usfi$rbv$1@smc.vnet.net>
On Sep 29, 4:13 am, John Fultz <jfu... at wolfram.com> wrote:
> On Tue, 28 Sep 2010 06:01:47 -0400 (EDT), Chris Degnen wrote:
> > Hi. Can anyone suggest how to test for the existence of a dialog?
>
> > In the example below a dialog is created containing a plot which can
> > be modified. However it seems to be difficult to test whether the
> > dialog has been closed.
>
> > This creates the dialog:
>
> > BeginPackage["TestExample`TestDialog`"];
> > CreateTestDialog::usage = "CreateTestDialog[] creates a test dialog";
> > Begin["`Private`"];
> > CreateTestDialog[] :=
> > Module[{}, n = 4;
> > CreateDialog[
> > plot = Dynamic[
> > ParametricPlot[{Sin[t], Sin[n t]}, {t, 0, 2 Pi}, Ticks -> None,
> > ImageSize -> 100]]]];
> > End[];
> > EndPackage[];
>
> > CreateTestDialog[];
>
> > And the plot can be modified by various means:
>
> > TestExample`TestDialog`Private`n = 8;
>
> > TestExample`TestDialog`Private`n = 2;
>
> > But how can I tell if the dialog has been closed? The dynamic plot
> > object still shows as existing afterwards:
>
> > NameQ["TestExample`TestDialog`Private`plot"]
>
> Yes, the name and even the value remain because they aren't scoped in any=
way.
> CreateDialog is not a variable scoping construct.
>
> If you want to poll to test whether it's been closed, you can do this usi=
ng the
> NotebookObject returned by your CreateTestDialog function. I.e.,
>
> nb=CreateTestDialog[];
> NotebookInformation[nb]
>
> This will return a list of values if the notebook is still open, and $Fai=
led if
> it's been closed. If you want to be notified as soon as the dialog clo=
ses, then
> the best way to do this is to implement a dialog with a DefaultButton[] a=
nd/or a
> CancelButton[].
>
> Sincerely,
>
> John Fultz
> jfu... at wolfram.com
> User Interface Group
> Wolfram Research, Inc.
Another possibility is to use the WindowClose event specification
inclusion in the Dialog's NotebookEventActions.
--David