Problems with QSortFilterProxyModel

[Nefastious]

Hi there guys,

I have a bit of a problem here I have a tiny problem here. I have a database connected to a QSqlTableModel, which in turn is connected to a QSortFilterProxyModel which in turn is connected to a QTableView. I also have the following code for deleting records:

void mainwindow::deletedialog() {
    QMessageBox::StandardButton button;
    button = QMessageBox::question(this, tr("Delete Record"),
                                   QString (tr("Are you sure you wish to delete this record?")),
                                   QMessageBox::Yes | QMessageBox::No);
 
    if (button == QMessageBox::Yes) {
        //Declaring an item selection which we will use to see which row the user has selected
        QItemSelection selection = ui->View->selectionModel()->selection();
        QList<int> rows;
        foreach ( const QModelIndex & index, selection.indexes() ) {
           rows.append( index.row() );
        }
 
        qSort( rows );
 
        int prev = -1;
        for( int i = rows.count() - 1; i >= 0; i -= 1 ) {
           int current = rows[i];
           if( current != prev ) {
              model->removeRows( current, 1 );
              prev = current;
           }
        }
    }
 
 
    else {
        QMessageBox::information(this, tr("Delete Record"), tr("Please select the record you wish to delete"));
    }
}

void mainwindow::deletedialog() {
    QMessageBox::StandardButton button;
    button = QMessageBox::question(this, tr("Delete Record"),
                                   QString (tr("Are you sure you wish to delete this record?")),
                                   QMessageBox::Yes | QMessageBox::No);

    if (button == QMessageBox::Yes) {
        //Declaring an item selection which we will use to see which row the user has selected
        QItemSelection selection = ui->View->selectionModel()->selection();
        QList<int> rows;
        foreach ( const QModelIndex & index, selection.indexes() ) {
           rows.append( index.row() );
        }

        qSort( rows );

        int prev = -1;
        for( int i = rows.count() - 1; i >= 0; i -= 1 ) {
           int current = rows[i];
           if( current != prev ) {
              model->removeRows( current, 1 );
              prev = current;
           }
        }
    }


    else {
        QMessageBox::information(this, tr("Delete Record"), tr("Please select the record you wish to delete"));
    }
}

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This code works fine unless we filter the contents of the table. If we have say 600 rows i the table, and we filter everything until we obtain 1 single record, then the code above may not delete the correct record. How can I make the above code work with QSortFilterProxyModel?

Any sample code would be greatly appreciated.

Thanks in advance,

Nefastious

[Lykurg]

Use QSortFilterProxyModel::mapToSource() to get the right index of you original model.

[Nefastious]

How exactly should I do that?

like this?

...
proxyModel->mapToSource();
model->removeRows( current, 1 );
...

...
proxyModel->mapToSource();
model->removeRows( current, 1 );
...

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[squidge]

originalindex = proxyModel->mapToSource(proxyindex);

where both originalindex and proxyindex are of type QModelIndex

[Lykurg]

How exactly should I do that?

like this?

...
proxyModel->mapToSource();
model->removeRows( current, 1 );
...

...
proxyModel->mapToSource();
model->removeRows( current, 1 );
...

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Before you just guess how to do, just follow the link and read:

QModelIndex QSortFilterProxyModel::mapToSource ( const QModelIndex & proxyIndex ) const

so in your case:

foreach ( const QModelIndex & index, selection.indexes() ) {
           rows.append( ui->View->model()->mapToSource(index).row() );
        }

foreach ( const QModelIndex & index, selection.indexes() ) {
           rows.append( ui->View->model()->mapToSource(index).row() );
        }

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[Nefastious]

I'm sorry I'm going to ask this I'll probably make you all very angry at me for being such a rookie... but the following code:

index = proxyModel->mapToSource(proxyModel->index());

index = proxyModel->mapToSource(proxyModel->index());

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just doesn't work. I get an error(/Users/k12yp70n/MedCare/MedAdmin/mainw.cpp:229: error: no matching function for call to 'QSortFilterProxyModel::index()'). I don't know what I am doing wrong. Please correct me but, find a solution having in mind the code I initially posted.

Thank you... and sorry for being such a newbie...

[Lykurg]

What do you expect to get by "proxyModel->index()"? the selected indices you get by the selection model how you have written in your example code. And by the way: Have you written it by yourself or just copy and pasted id? Have you tried my suggestion with your code? (supposing you have set the proxy model...)

[Nefastious]

terribly sorry sir... i didn't read your post...

Now that I have tried the code:

rows.append( ui->View->model()->mapToSource(index).row() )

rows.append( ui->View->model()->mapToSource(index).row() )

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;

my compiler tells me that model has no member named mapToSource...

Again what am I doing wrong?

And once again please accept my apologies for having failed to read your post, and, I must sincerely thank you for all of your wisdom, knowledge, support and patience.

[squidge]

Doesn't model() return a QAbstractItemModel, whereas you want a QAbstractProxyModel to get mapToSource? QAbstractProxyModel inherits from QAbstractItemModel, so...

QAbstractProxyModel *q = dynamic_cast<QAbstractProxyModel*>(ui->View->model());
if (q) q->mapToSource(...)
else q isn't a valid pointer to a QAbstractProxyModel

QAbstractProxyModel *q = dynamic_cast<QAbstractProxyModel*>(ui->View->model());
if (q) q->mapToSource(...)
else q isn't a valid pointer to a QAbstractProxyModel

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Just a guess...

[Lykurg]

my bad. You must cast ui->View->model() to QAbstractItemModel or it your be easier if you would store a pointer to the sort model as a member variable, e.g. m_sortModel.

EDIT: I'm too late, and yes, fatjuicymole, you are right.

[Lykurg]

QAbstractProxyModel *q = dynamic_cast<QAbstractProxyModel*>(ui->View->model());

QAbstractProxyModel *q = dynamic_cast<QAbstractProxyModel*>(ui->View->model());

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Since the model includes QObject it is better to use qobject_cast since

The qobject_cast() function behaves similarly to the standard C++ dynamic_cast(), with the advantages that it doesn't require RTTI support and it works across dynamic library boundaries.

But in that case I would use static_cast.