Re: a TreeModel that's sortable and filterable?

[Armin Burgmeier <armin arbur net>]

On Fri, 2008-06-13 at 18:13 -0500, Joaquim Schmidlap wrote:
> It looks like TreeModelFilter and TreeModelSort are separate  
> derivations from TreeModel...pity.

TreeModelFilter and TreeModelSort have child models. So, if you have
some TreeModel A, and you want it sorted, then create a TreeModelSort
with A as child. If you want it both sorted and filtered, then create a
TreeModelFilter with a TreeModelSort as child (or vice versa).

Note that Gtk::ListStore and Gtk::TreeStore already support sorting
(since they implement Gtk::TreeSortable), so you don't even need
Gtk::TreeModelSort for them (unless you want to do things like showing a
sorted and an unsorted model in different views).

> If I wanted a TreeModel to be sortable and filterable, what's the  
> best way forward? I assume I'd have to pick one and add the  
> functionality of the other myself, or perhaps do something with  
> multiple inheritance. What is recommended here? What's easiest?
> 
> And, I realize this calls for speculation, but can anyone say why  
> this design decision was made? Seems like what I want to do would be  
> relatively common.

Armin