[PyQt] Trouble reading a model index from an "untouched" combo box

[Andreas Pakulat]

On 27.01.10 09:08:13, Claudio Felix wrote:
> 2010/1/27 Andreas Pakulat <apaku at gmx.de>:
> > On 26.01.10 17:41:40, Demetrius Cassidy wrote:
> >> I don't think you need to use the view pointer at all - it's
> >> returning QAbstractItemView *, which I would assume it would need to
> >> be casted to the proper class in C++. If that's so, by design the
> >> Abstract class will return an invalid index.
> >
> > I don't think so ;) The function currentIndex on the view is not
> > virtual, so its implemented in the abstract class already properly.
> >
> > And to get a model index to index into the model its easier to ask the
> > view for it, rather than constructing it yourself with model->index(
> > combobox->currentIndex(), <model-column>, QModelIndex())
> >
> > Andreas
> >
> 
> Andreas,
> 
> That was the way I was thinking when I tried the code in the beggining
> of this thread.. but I'm still stuck retrieving an invalid index if I
> don't at least click on the combo box (if I do click on it I get a
> valid index just fine).
> 
> If you take a look at the code, my intent was to get the ITEM_ID
> field, which is the table's primary key which corresponds to the item
> selected on the combo box. Since I have the model for the table
> already, I found natural to use it for displaying the ITEM_NAME field
> on the combo box, so I would get the selected item model index from
> its view to get the ITEM_ID from the table model and use it to
> optionally filter data on a subsequent SQL Query. I'm intrigued by
> this QComboBox behavior, for the model was given a "select()" before
> being associated to it, so I think it should return a valid index.

Well, the combobox has initially no selected/current entry - AFAIK. Only
once you select one it'll be set. Hence the invalid index.

However a setCurrentIndex with a value != 0 on the combobox should
change that already I think.

Another thing in your case is that box.view().currentIndex() will not be
an index that contains the ITEM_ID value, because the current index will
be pointing to the name-cell. Each index indvidually refers to a single
cell and you've used the ITEM_NAME column for the combobox, so its view
will only give you indexes from that column.

Andreas

-- 
You plan things that you do not even attempt because of your extreme caution.