Qt getting reference of custom data type of QStandardItemModel to change it!

Question

It's getting a little weird I can't see a method to actually change the "data" of a QStandardItemModel. For example:

struct TestStruct {
    std::vector<int> testVector;
    void addNumber(int i){  
        //this method will modify the member vector
    }
};
Q_DECLARE_METATYPE(TestStruct)

QStandardItemModel* model = QStandardItemModel(1,1);
QModelIndex index = model->index(0,0);
TestStruct test;
test.addNumber(1);
model->setData(index, qVariantFromValue(test));

With that, I will effectively have added a std::vector with the number 1 to the index {0,0} of the model. But how would I add another number to that TestStruct's vector from places that don't have access to the TestStruct instance anymore?

The "data" function returns a QVariant that can be casted as a TestStruct but its a copy and I need a reference... get it?

Thanks for the help.

Answer 1

Yes it will return the value only and not it's reference.

A workaround for this is, you can get the struct by Typecasting the QVariant. Then modify your testVector.

After modifications, call again

model->setData(index, qVariantFromValue(newTest));

where newTest is your struct with the modified Vector.

Hope it helps.