Passing Model to a Dialog. View does not get updated properly

[sandro4912]

Ok I have the following Issue:

I have a MainWindow were I use a Model derrived from QSqlTableModel.

MainWindow::MainWindow()
    :mQuestionModel{ new QuestionSqlTableModel{ this } },
    mPictureDelegate{ new PictureDelegate }
{   
    mQuestionModel->setTable("questions");
    mQuestionModel->setSort(QuestionColumn::id, Qt::AscendingOrder);
    mQuestionModel->setHeaderData(
                QuestionColumn::askedQuestion, Qt::Horizontal, tr("Question"));
    mQuestionModel->setHeaderData(
                QuestionColumn::answer1, Qt::Horizontal, tr("Answer1"));
    mQuestionModel->setHeaderData(
                QuestionColumn::answer2, Qt::Horizontal, tr("Answer2"));
    mQuestionModel->setHeaderData(
                QuestionColumn::answer3, Qt::Horizontal, tr("Answer3"));
    mQuestionModel->setHeaderData(
                QuestionColumn::answer4, Qt::Horizontal, tr("Answer4"));
    mQuestionModel->setHeaderData(
                QuestionColumn::correct_answer, Qt::Horizontal,
                tr("Correct Answer"));
    mQuestionModel->setHeaderData(
                QuestionColumn::picture, Qt::Horizontal, tr("Picture"));

    mQuestionModel->select();

//....

When the user pushes a Action I create a QTableView were the user can see existing entries and edit them.

So far so good this all seems to work.

Now i want to open a Dialog to have the user add more entries into database.

void MainWindow::addQuestions()
{
    auto addNewQuestionDialog = new AddNewQuestionDialog{ mQuestionModel };
    addNewQuestionDialog->setAttribute(Qt::WA_DeleteOnClose);

    addNewQuestionDialog->show();
    addNewQuestionDialog->exec();
}

My Idea was to pass the Model to the Dialog and write directly into the database with insertRecord when accept happens:

void AddNewQuestionDialog::accept()
{
    auto picturePath = ui->fileNamelineEdit->text();

    QByteArray picture;
    if(!picturePath.isEmpty()) {
       QPixmap inPixmap;
       if (inPixmap.load(picturePath)) {
           QBuffer inBuffer(&picture);
           inBuffer.open( QIODevice::WriteOnly );
           inPixmap.save(&inBuffer, "PNG");
       }
    }

    mModel->database().transaction();

    auto record = mModel->record();
    record.field("id").setAutoValue(true);
    record.setValue(QuestionColumn::askedQuestion, ui->questionLineEdit->text());
    record.setValue(QuestionColumn::answer1, ui->answer1LineEdit->text());
    record.setValue(QuestionColumn::answer2, ui->answer2LineEdit->text());
    record.setValue(QuestionColumn::answer3, ui->answer3LineEdit->text());
    record.setValue(QuestionColumn::answer4, ui->answer4LineEdit->text());
    record.setValue(QuestionColumn::correct_answer, correctAnswerAsInt());
    record.setValue(QuestionColumn::picture, picture);

    if(!mModel->insertRecord(-1, record)) {
        qDebug() << "Failed to set record" <<
             "The database reported an error: " <<
               mModel->lastError().text()
        <<"RowCount" <<mModel->rowCount();
    }

    if(mModel->submitAll()) {
        mModel->database().commit();
    }
    else {
        mModel->database().rollback();
                qDebug() << "Database Write Error" <<
                     "The database reported an error: " <<
                       mModel->lastError().text();
    }

    QDialog::accept();
}

After the dialog closes the model gets updated but instead of showing a new number in the rows it shows a new empty entry with a !

If i restart the app or look into the database the entry was correctly added.

Is the view out of sync?

Is it a bad practice to pass the model to the Dialog?

[JonB]

@sandro4912
I'm not sure what's wrong in your code. It should be fine to pass the model (pointer) around as a parameter. For now, you don't show where you create the view ("I create a QTableView" --- it hasn't gone out of scope, has it?) and how you attach it to the model, check its https://doc.qt.io/qt-5/qabstractitemview.html#rowsInserted slot is being called and what the row data looks like? Try an explicit mQuestionModel->select() after the commit(), or back in main when mQuestionModel->select() returns? Immediately after the commit(), verify what the value in record.field("id") is, it should be getting updated from the database?

[sandro4912]

You are right adding mModel->select(); after the mModel->database().commit(); seems to update the View properly to the new data.

However this is still weired. Why without it the View adds a row with a !? So it nows theres a new record but it does not know about the new data?

record.field("id").setAutoValue(true); was not necessary since id is auto generated so i removed it.