[Interest] Binding based on typeof doesn't work any more

mail at herrdiel.de mail at herrdiel.de
Thu Oct 17 09:20:44 CEST 2019


I have a simple Label that has to show a property of a rootProperty, the latter not yet being created when the qml is loaded/created. Quite frequently I use this construct and it did work perfectly in older Qt versions (something before 12.1 - that's the earliest I have installed now):
//[main.qml, inside a Label]
text: typeof Controller === "undefined" ? "" : Controller.successfulSteps
Now this doesn't show anything anymore. The following workaround does show the desired result:
property string dummy: ""
text: dummy+(typeof Controller === "undefined" ? "" : Controller.successfulSteps)
This seems very hackish. Is there a better way to achieve this? Why has the behavior been (apparently) changed at all in the first place?
The Controller has been set as a root property after loading the QML page:
QQmlApplicationEngine engine;
Controller controller(&engine);
engine.rootContext()->setContextProperty("Controller", QVariant::fromValue<Controller*>(&controller));

I've asked this in forum.qt.io before (https://forum.qt.io/topic/107828/binding-based-on-typeof-doesn-t-work-any-more)


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