QJsonObject derived class copy of

[SPlatten]

I have created a class which is derived from QJsonObject. I want to initialise the class from another instance of QJsonObject, however I'm getting errors.

The code:

        QVariant varProperty(property(clsQtTable::mscszPropertyChanges));
        Q_ASSERT_X(varProperty.isValid()==true, cszDebugName, "No changes property!");
    //Initialise change management object
        mobjChangeMgnt = varProperty.toJsonObject();

On the last lint the error displayed in Qt Creator:

clsQtTable.cpp:320: error: No viable overloaded '='

My class prototype so far:

    class clsQtProperties : public QJsonObject {
    private:
        bool blnFind(const QString& crstrKey, QJsonObject::Iterator& rIterator);

    public:
        static const char mscszKeyDelimiter[];

        clsQtProperties();

        bool blnCheckForChange(const QString& crstrKey, const QString& crstrData);
        bool blnGetFromKey(const QString& crstrKey, int& intColumn, QString& rstrPrimaryKey);
        bool blnSetData(const QString& crstrKey, const QString& crstrData
                       ,bool blnInitial = false);
        static QString strBuildKey(int intColumn, const QString& crstrPrimaryKey);
    };

This is the prototype for the class for mobjChangeMgnt.

[SPlatten]

@Christian-Ehrlicher , fixed, modified prototype (Just new additions):

        clsQtProperties(const QJsonObject& crobjOriginal);

        clsQtProperties operator = (QJsonObject& initialiser);

Implementation:

clsQtProperties::clsQtProperties(const QJsonObject& crobjOriginal) {
    for( QJsonObject::const_iterator cit(crobjOriginal.begin())
       ; cit!=crobjOriginal.end(); cit++ ) {
        insert(cit.key(), cit.value());
    }
}

clsQtProperties clsQtProperties::operator= (const QJsonObject& crobjInitialiser) {
    *this = clsQtProperties(crobjInitialiser);
    return *this;
}

[Christian Ehrlicher]

@SPlatten said in QJsonObject derived class copy of:

No viable overloaded '='

Then you should create this overload (and for design reason also a ctor taking a QJsonObject) . How should the compiler know how to convert from one type into the other otherwise?

[SPlatten]

@Christian-Ehrlicher , I thought because the class prototype states it is derived from QJsonObject that the compiler would know this from the prototype?

Can you help me with how or what I need to do ?

[Christian Ehrlicher]

@SPlatten Your answer would imply that a compiler knows how to create a QLabel out of a QObject by itself.

[SPlatten]

@Christian-Ehrlicher , fixed, modified prototype (Just new additions):

        clsQtProperties(const QJsonObject& crobjOriginal);

        clsQtProperties operator = (QJsonObject& initialiser);

Implementation:

clsQtProperties::clsQtProperties(const QJsonObject& crobjOriginal) {
    for( QJsonObject::const_iterator cit(crobjOriginal.begin())
       ; cit!=crobjOriginal.end(); cit++ ) {
        insert(cit.key(), cit.value());
    }
}

clsQtProperties clsQtProperties::operator= (const QJsonObject& crobjInitialiser) {
    *this = clsQtProperties(crobjInitialiser);
    return *this;
}

[JonB]

@SPlatten
I am not as expert at C++ as some, but I think you should write your operator = to take a const parameter for the QJsonObject& initialiser.

[SPlatten]

@JonB , thank you, will add that.