How to add one empty row in ComboBox with model

Hi again :)

I've a ComboBox fill by QSqlQueryModel:

Code:

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ComboKierowcy = new QComboBox(parent);
  QSqlQueryModel *ComboKierowcyModel = new QSqlQueryModel();
 
  ComboKierowcyModel->setQuery( "SELECT * FROM kierowcy ORDER BY Nazwisko" );
  if (ComboKierowcyModel->lastError().isValid())
    qDebug() << ComboKierowcyModel->lastError();
 
  QModelIndex tmp;
  ComboKierowcy->setModel(ComboKierowcyModel);
  ComboKierowcy->setModelColumn(1);

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Everything is ok, but I need a one empty position on the first place. How add this?

You will have to subclass QSqlQueryModel and reimplement data() and rowCount() and perhaps some more methods. You can do something like this:

In myquerymodel.h file:

Code:

---

#include <QSqlQueryModel>
 
class MyQueryModel : public QSqlQueryModel
{
    Q_OBJECT
 
public:
    MyQueryModel(QObject *parent = 0);
 
    virtual QVariant data(const QModelIndex& item, int role = Qt::DisplayRole) const;
    virtual int rowCount(const QModelIndex& parent = QModelIndex()) const;
};

---

In the myquerymodel.cpp file:

Code:

---

MyQueryModel::MyQueryModel(QObject *parent) : QSqlQueryModel(parent)
{
}
 
QVariant MyQueryModel::data(const QModelIndex& item, int role) const
{
    if(item.row() == 0)
        return QVariant();
 
    QModelIndex fakeItem = this->QSqlQueryModel::index(item.row()-1, item.column());
    return this->QSqlQueryModel::data(fakeItem, role);
}
 
int MyQueryModel::rowCount(const QModelIndex& parent) const
{
    return this->QSqlQueryModel::rowCount(parent) + 1;
}

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