Problems with QSqlRelationalTableModel

[certqt]

Hi, sorry for the late reply to this post but I was struggling with the same problem and think I have worked out the solution.

The problem seems to be that the QDataWidgetMapper doesn't re-populate itself correctly after updates to the model when the submit policy is QDataWidgetMapper::AutoSubmit. This is true of both the standard item delegate and the QSqlRelationalDelegate (which just calls the standard delegate if it is not populating a combo box anyway).

To get a QLineEdit to work well with a QDataWidgetMapper and a QRelationalTableModel it is necessary to subclass either QItemDelegate or QSqlRelationalDelegate as follows:

void MyItemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
    if (!strcmp(editor->metaObject()->className(),"QLineEdit")) {
        QLineEdit *le = qobject_cast<QLineEdit *>(editor);
        le->setText(index.data().toString());
    }
    else
        QItemDelegate::setEditorData(editor, index);
}

void MyItemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
    if (!strcmp(editor->metaObject()->className(),"QLineEdit")) {
        QLineEdit *le = qobject_cast<QLineEdit *>(editor);
        le->setText(index.data().toString());
    }
    else
        QItemDelegate::setEditorData(editor, index);
}

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Then install MyItemDelegate in the same way as you installed QSqlRelationalDelegate:

mapper->setItemDelegate(new MyItemDelegate);

mapper->setItemDelegate(new MyItemDelegate);

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Hope this helps someone, or if I have got something wrong I would be happy to hear why.