Serialization and inheritance using Qt

[high_flyer]

So when I serialize this list, how do I make sure it's actually ChildClass1 or ChildClass2 instances beeing serialized ?

one way is to have the base class declare an 'm_type' variable (an enum would be convenient) that the inheriting classes must define - which you then can ask for and based on the type make the correct cast.
Once the pointer is casted, the correct stream operator will be used automatically.

[totem]

@tbscope : thank you for your suggestions. However, I want to keep the QDataStream support; if i'm right it will also open me doors of drag/drop support

@high_flyer : I do have this system, so I will use the solution to switch on object->type() and instanciate DerivedClass accordingly. It's inelegant but if it works...

[wysota]

@tbscope : thank you for your suggestions. However, I want to keep the QDataStream support; if i'm right it will also open me doors of drag/drop support

Using QDataStream instead of any other serialization form doesn't help in any way to handle drag&drop. In either case you end up with a block of bytes, it's just a matter of which mechanism populates the blob but nothing happens on its own, you have to write code that does it yourself.

If you want to use QDataStream in this specific case then your base-class has to know all its potential subclasses and handle conversions between them and itself. This is of course possible but it's quite a lot of work so if you don't feel comfortable with the topic, I wouldn't recommend this approach.

[totem]

Using QDataStream instead of any other serialization form doesn't help in any way to handle drag&drop

Yes I'm sorry. I meant I want to be able to use these classes with qRegisterMetaTypeStreamOperators(), I use it for drag/drop.

If you want to use QDataStream in this specific case then your base-class has to know all its potential subclasses

My project is not that huge, it's a matter of a dozen classes for now.
I was just wondering if there existed elegant C++/Qt solution with QDataStream serialization and inheritance.

Thank you all for your answers