[Qt-interest] How to remove items from QSqlTableModelvia QTableView

[Malyushytsky, Alex]

According to my understanding it does not work, because the way you remove rows changes indexing.
For example if u need to remove rows 3,4,7, and are trying to remove 3 first,  row 4 becomes 3, 7 becomes 6.

To fix  problem try to remove the rows  in decrementing order, something like
for ( int row = tmp.size()-1; row >-1; row--)
{ ..........
}

Also, according to the documentation selectedIndexes() do not contain duplicates, but is not sorted.
So you would need to pre-sort it.

I would say that even you can make this approach work, it is not at efficient.
What I would do, instead of using selectedIndexes() I would iterate (in reverse direction) through the each index,
check if it is selected, remove it.

Hope this helps,
     Alex



From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Sven Grunewaldt
Sent: Monday, April 27, 2009 12:06 PM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] How to remove items from QSqlTableModelvia QTableView

Hi,

actually this doesn't seem to work and I again don't understand why ;)

My function:
---
void BerichteOrk::removeSelectedFromTableView(QTableView* view)
{
    QAbstractItemModel* model = view->model();

    const QModelIndexList tmp = view->selectionModel()->selectedIndexes();
    QList<QPersistentModelIndex> indexes;

    for (int i = 0; i < tmp.size(); i++)
    {
        qDebug() << tmp.at(i).internalId() << tmp.at(i).isValid() << tmp.at(i).row();
        indexes.append(QPersistentModelIndex(tmp.at(i)));
        qDebug() << tmp.at(i).internalId() << tmp.at(i).isValid();
    }
    qDebug() << "";
    for (int i = 0; i < indexes.size(); i++)
    {
        qDebug() << indexes.at(i).internalId() << indexes.at(i).isValid() << indexes.at(i).row();
        model->removeRow(indexes.at(i).row());
        qDebug() << indexes.at(i).internalId() << indexes.at(i).isValid();
    }

    view->resizeColumnsToContents();
    view->resizeRowsToContents();
    view->horizontalHeader()->setStretchLastSection(true);
}
---

qDebug() output:
---
0 true 1
0 true
0 true 2
0 true
0 true 3
0 true
0 true 4
0 true

0 true 1
0 false
0 false -1
0 false
0 false -1
0 false
0 false -1
0 false
---

As I understand the documentation this _should_ work...

Regards,
Sven Grunewaldt

Am 27.04.2009 01:15, schrieb Tony Rietwyk:
Hi Sven,

Correct me if I'm wrong, but I don't think you should make any assumptions about the order of the indexes returned from selectedIndexes.

I suggest converting them to persistent indexes first, that way subsequent indexes will get updated by the view as you delete them.

Hope that helps,

Tony.

-----Original Message-----
From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Sven Grunewaldt
Sent: Sunday, 26 April 2009 01:58
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] How to remove items from QSqlTableModelvia QTableView
Haha, oh god. I can't believe I didn't notice this... Thanks! :)
Sometimes you need another pair of eyes to see the obvious.

Regards,
Sven Grunewaldt

Am 25.04.2009 17:50, schrieb Scott Aron Bloom:
Your algorithm fails for the same reason this algorithm fails:

QList< int > values;
//make a list where value[ ii ] == ii
for( int ii = 0; ii < 10; ++ii )
   values << ii;


// remove value 3, 4, 5
values.removeAt( 3 );
values.removeAt( 4 );
values.removeAt( 5 );

// which actually removes 3,5 and 7 (I think... :) )
The problem is, since you are removing index.row() 1 at a time, your row
value will most likely NOT be valid after the remove.


Scott



-----Original Message-----
From: qt-interest-bounces at trolltech.com [mailto:qt-interest-
bounces at trolltech.com] On Behalf Of Sven Grunewaldt
Sent: Saturday, April 25, 2009 8:31 AM
To: qt-interest at trolltech.com
Subject: [Qt-interest] How to remove items from QSqlTableModel via

QTableView

Hi,

I have a QTableView which lies on top of a QSqlTableModel and a Button
to remove the currently selected rows. It seems that my implementation
of the buttons function does something wrong.
Sometimes not all selected items are removed and I just can't see why,
maybe someone finds my mistake:

void BerichteOrk::on_removeSchuleButton_clicked()
{
     const QModelIndexList tmp =
schuleView->selectionModel()->selectedIndexes();

     foreach (QModelIndex index, tmp)
     {
         schuleModel->removeRow(index.row());
     }
}

Regards,
Sven Grunewaldt

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