QComboBox *cb=new QComboBox();
                cb->setModel(this->productModel);
                cb->setModelColumn(1);
                cb->setEditable(true);
                cb->setAutoCompletion(true);
                cb->setAutoCompletionCaseSensitivity(Qt::CaseInsensitive);
                cb->completer()->setCompletionMode(QCompleter::PopupCompletion);

void EventDialog::popUpIndex(QModelIndex s)
{
    QCompleter * cl = qobject_cast<QCompleter * >(sender());
    QComboBox * cb = qobject_cast<QComboBox * >(sender()->parent());
 
    int completer_id=cl->completionModel()->data(cl->completionModel()->index(s.row(),0)).toInt();
 
    QModelIndexList indexList = cb->model()->match(cb->model()->index(0,0), Qt::DisplayRole, completer_id, 1, Qt::MatchExactly);
    if(indexList.count())
    {
        QModelIndex index=indexList.first();
        cb->setCurrentIndex(index.row());
    }
}