How to use QMetaMethod with QObject::connect

This has been fixed as of Qt 4.8.0:

https://bugreports.qt.io/browse/QTBUG-10637

Suppose we have a QObject* m_subject, and wish to connect the change-notification signal of a property to a propertyChanged() slot:

const QMetaObject* meta = m_subject->metaObject();
QMetaProperty prop = meta->property(meta->indexOfProperty("myProperty"));
if (prop.hasNotifySignal()) {
    QMetaMethod signal = prop.notifySignal();
    QMetaMethod updateSlot = metaObject()->method(
        metaObject()->indexOfSlot("propertyChanged()"));
    connect(m_subject, signal, this, updateSlot);
}

I successfully used this to make a QWidget subclass which finds all the properties of any QObject and creates a QLineEdit for each of them, with a connection to keep the QLineEdit updated whenever the corresponding property changes. (Because I didn't find a way to pass a propertyID value to propertyChanged() though, it was necessary to make a subclass of QLineEdit and implement propertyChanged() there. QSignalMapper didn't help, because all the properties are in the same object.)