Using QComboBox with QSqlQueryModel

Question

To speed-up QComboBox work with very big data set want to try to use QSqlQueryModel instead of QStandardItemModel. However text data in QComboBox I need to map to an ID, which is stored and accessible currently by itemData(rowIndex, Qt::UserRole). In QSqlQueryModel query there will be 2 columns: ID and Text; and QComboBox setModelColumn(1) is defined, i.e. Text.

How to correctly subclass or redefine QSqlQueryModel, if combobox->itemData(rowIndex, Qt::UserRole) have to contain ID? Who had implemented such things or know link to a source? If I define QVariant QSqlQueryModel::data(const QModelIndex & item, int role = Qt::DisplayRole) in a such way:

QVariant MySqlModel::data(const QModelIndex &index, int role) const
{
    if(role == Qt::UserRole && index.column() == 1)
         return QSqlQueryModel::data(this->index(index.row(), 0), Qt::DisplayRole);

    return QSqlQueryModel::data(index, role);
}

will it work, i.e. whether combobox->itemData(rowIndex, Qt::UserRole) will contain ID in this case? Or need to investigate Qt sources?

Answer 1

Yeah, according to QComboBox code should work:

QVariant QComboBox::itemData(int index, int role) const
{
    Q_D(const QComboBox);
    QModelIndex mi = d->model->index(index, d->modelColumn, d->root);
    return d->model->data(mi, role);
}

Will implement this.