Title: Best Practice for Sending Data from C++ to QML – Many Changeable Components
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Hi everyone,
I’m working on a Qt application where the UI is written in QML and the backend logic is implemented in C++. I have many changeable UI components in QML that need to be updated from C++ in real-time (like labels, states, visibility, styles, etc.).
I’ve explored two main approaches:
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Using Q_PROPERTY with Q_OBJECT classes to expose each property to QML
→ This works but leads to a large number of Q_PROPERTY declarations, which feels unmanageable as the project scales. -
Using a QAbstractListModel
→ This seems like the cleanest option to me, especially for repeating items, but I struggle with binding individual values directly to QML elements (e.g. Text { text: modelData.someField } doesn't update properly).
My Questions:
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What is the best practice in Qt for sending many different data fields or UI states from C++ to QML, especially when the UI is dynamic?
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Is there a way to use QAbstractListModel effectively for this, especially when the UI is not a list but consists of many components?
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Is it better to use QVariantMap, a QAbstractListModel, or create custom QObject classes with grouped properties?
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Is there any efficient data-binding technique (e.g., via Connections, Binding, or ContextProperty) that can reduce the boilerplate?
Any insights, examples, or recommendations based on real-world projects would be appreciated!
Thanks
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The most natural way in QML is a model-view approach. If that at all fits your use case it is usually the cleanest way to go.
The UI does not need to be a list (view) as such in order to be driven by a list model. You could use a
Repeater-based approach for example.You said you struggled to get the bindings to a list model to work properly. This is almost certainly because of something fairly simple that you are doing wrong, so I would advise persevering with that to find out what the problem is. Reduce it down to a simple case and post it here if you are still struggling.