typeid meets heritage

Walux

Hi Qt Community :)

Sorry for the lazy post but ,
i spent a long time searching for a solution to this simple issue :

if(typeid(*(element)) == typeid(motherClass))
        doSmth();

The typeid can only identify the motherClass instances , and not its childs (inheriting classes)

How to fix this obvious issue ?
Nice regards :)

SGaist

Hi,

What do you want to achieve ? Call doSmth if element is a derived class of motherClass ?

Walux

@SGaist

Yes , I want it called if element's derived of MotherClass , or it IS motherClass .

Chris Kawa

if (dynamic_cast<motherClass*>(element))
    doSmth();

or, in case of QObject derived classes

if (qobject_cast<motherClass*>(element))
    doSmth();

Walux

@Chris-Kawa

Does this trick work even if my class is derived of both QObject , and QGraphicsitem ? Because compiler gives me that known warning that object_cast won't work unil i implement the type() method .

Chris Kawa

As I said - qobject_cast works only for QObject derived classes. QGraphicsItem does not derive from QObject. For that you need a dynamic_cast.

Walux

@Chris-Kawa

Thank you very much , works like a charm :)