Re: Gtk::TreeModel oddity

[Murray Cumming <murrayc murrayc com>]

On Wed, 2005-04-27 at 10:11 -0500, Bob Caryl wrote:
> Hello all,
> 
> I have an application where I use a Gtk::ListStore in conjunction with a 
> Gtk::TreeView to display representations of records in a database.  I 
> have a function whereby the user can delete database records by clicking 
> on one of those representations and pressing a button.  In the function 
> connected to that button, I use the following code to remove the list 
> store entry representing the deleted database record and to set the Tree 
> View cursor:
> 
> 
> Glib::RefPtr<Gtk::ListStore> list;                                // our 
> listore object for the treeview
> Glib::RefPtr<Gtk::TreeSelection> list_sel;                  // selection 
> for the treeview
> 
> Gtk::TreeModel::Path *path = new 
> Gtk::TreeModel::Path(list->erase(list_sel->get_selected()));  // obtain 
> path to the row following the deleted row
>    
I'd start by checking the result of get_selectd(), and the result of
erase() for validity, with if(iter).

> if(path)   // if the path is valid set the view cursor to that path.
> {
>     tree->set_cursor(*path);
>     delete path;
> }
> 
> 
> This code works (e.g. the row in the TreeView disappears and the cursor 
> is repositioned on the following row), but I get several "Critical" 
> messages:
> 
> (gmwadmin:2454): Gtk-CRITICAL **: gtk_list_store_get_value: assertion 
> `GTK_LIST_STORE (tree_model)->stamp == iter->stamp' failed

This normally means that the iterator is from a different treemodel.
Maybe you are using a different model here by mistake.

> (gmwadmin:2454): GLib-GObject-CRITICAL **: g_value_get_string: assertion 
> `G_VALUE_HOLDS_STRING (value)' failed
> (gmwadmin:2454): GLib-GObject-CRITICAL **: g_value_unset: assertion 
> `G_IS_VALUE (value)' failed
> (gmwadmin:2454): Gtk-CRITICAL **: gtk_list_store_get_path: assertion 
> `iter->stamp == GTK_LIST_STORE (tree_model)->stamp' failed
> (gmwadmin:2454): Gtk-CRITICAL **: gtk_tree_view_set_cursor_on_cell: 
> assertion `path != NULL' failed
> 
> Using the de-bugger I have determined that the call to "list->erase" is 
> generating these messages.    The messages tend to make me think that 
> the iterator returned by the Gtk::TreeSelection::get_selected function 
> is not the same type of iterator required by the Gtk::ListStore::erase 
> function as its formal parameter.  However, the docs don't seem to make 
> a distinction between the iterators they describe as return values and 
> formal parameters (in other words, following the hyperlinks in the docs 
> to the iterators go to the same page).  I *think* I have implemented the 
> foregoing code properly based on the gtkmm docs, but maybe I have not... 
> can someone please point out my error?
> 
> Best regards,
> Bob Caryl
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-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com