Re: Using a TreeStore with a ComboBox

[Jef Driesen <jefdriesen hotmail com>]

Jonathon Jongsma wrote:
> On 6/22/07, Jef Driesen <jefdriesen hotmail com> wrote:
> > Jonathon Jongsma wrote:
> > > On 6/21/07, Jef Driesen <jefdriesen hotmail com> wrote:
> > > > Using a treestore model with a combobox creates a nice dropdown list
> > > > with submenus. Inside each submenu, the parent item is shown with a
> > > > separator below to separate it from its children. I want to know how I
> > > > can hide this parent node, so I can only select leaf nodes (e.g items
> > > > without children).
> > > >
> > > > The model contains places that can be are arranged by the user in an
> > > > arbitrary hierarchy, to group related places together (for instance by
> > > > continent and/or country). This is very similar how files (my places)
> > > > can be arranged into directories (my hierarchy). But when the user needs
> > > > to select a place with the combobox, it doesn't make sense to be able to
> > > > select an item that is not a place.
> > > You could probably accomplish this fairly easily with TreeModelFilter
> > > (http://gtkmm.org/docs/gtkmm-2.4/docs/reference/html/classGtk_1_1TreeModelFilter.html)
> > > wrapping your existing treestore. You'd just need to provide a
> > > function which checks whether a node has children or not, and pass
> > > that function to TreeModelFilter::set_visible_func().  Hope that
> > > helps.
> > I tried a TreeModelFilter like this:
> >
> > Glib::RefPtr<Gtk::TreeStore> store = Gtk::TreeStore::create(m_columns);
> > Glib::RefPtr<Gtk::TreeModelFilter> filter = Gtk::TreeModelFilter::create
> > (store);
> > filter->set_visible_func (sigc::mem_fun(*this, &Example::on_model_visible
> > combo.set_model(filter);
> >
> > bool
> > Example::on_model_visible (const Gtk:TreeModel::const_iterator& iter)
> > {
> >     return iter->children().empty();
> > }
> >
> > But it doesn't work. Exactly the same tree structure is shown if the
> > model is populated after the set_visible_func. Or the combobox is
> > completely empty, if the tree is populated before that.
>
> does it work if you explicitly call TreeModelFilter::refilter() after
> populating the model?  I'm not sure whether this should be necessary,
> but it might give you a clue as to what's not working...

After refilter, the combobox contains no items anymore, just like when I 
populate the model before using set_visible_func. This is what I 
expected, because in my model all toplevel nodes have children. Of 
course this is not the solution I need.