Loading (e. g. a qtreeview) model data in a different thread

[dubbaluga]

No, that's not a good idea. You should prepare the data in external thread and signal the model object that it can consume what's prepared for it so that the modification to the model happens in the main thread.

So, it's working for me now. I'm passing the underlying data structure of my QAbstractItemModel object, which is an instance of a composite pattern class to the worker thread so that it can add additional elements to it.
Before doing so, the beginResetModel() method is invoked. After adding the elements, the endResetModel() method of my QAbstractItemModel instance is invoked.

What helped me a lot was actually the point, that GUI parts have to stay in the main thread (GUI thread). In case I want to display some "work in progress" message, I'm using Signals/Slots between my worker thread and main thread, as mentioned here.

As I'm actually programming with PySide, further relevant links can be found here:

• Signals and Slots in PySide
• How to emit cross-thread signals in Qt (C++)
• New-style signals: no Signal.connect()?

Thanks for your help! Best regards, Rainer