Re: Gtk2::ComboBox - setting value by string?

[muppet <scott asofyet org>]

On Aug 8, 2006, at 10:17 PM, Daniel Kasak wrote:

> John M. Burian wrote:
> > It doesn't fix the 'bug', such as it is, but a technique I use is  
> > to, as
> > I'm adding values to the ListStore, create a hash that maps the  
> > strings
> > back to the indicies of the ListStore, then add a reference to  
> > that hash
> > to the ComboBox object.
> >
> > $list = Gtk2::ListStore->new ("Glib::String");
> > map {
> >   $list->set ($iter = $list->append, 0, $_);
> >   $$href{$_} = $list->get_string_from_iter ($iter);
> > } (qw/Option1 Option2 Option3/);
> > $combobox = Gtk2::ComboBox->new_with_model ($list);
> > $combobox->{hash} = $href;
> >
> > Then later, to set the value of the combobox using the string:
> >
> > $combobox->set_active ($combobox->{hash}{'Option1'});

This relies on both perl's implicit conversion from strings to  
integers and the fact that list paths have only one index, so the  
path string converts cleanly to an integer.

> Are you allowed to do this? I've read in a number of places that it's
> dangerous to keep iters around for any length of time ... ie that they
> are only valid immediately.

He's calling Gtk2::TreeModel::get_string_from_iter(), which returns  
"a string representation of an iter":
http://developer.gnome.org/doc/API/2.0/gtk/GtkTreeModel.html#id3249895

This is actually equivalent to  $model->get_path ($iter)->to_string 
().  It's safe to save treepath objects, because they are just lists  
of integer indices, but it is important to remember that the indices  
are invalid when the model is altered.



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