Bindings not updating when property notify signal is emitted

patrickkidd

I have a situation where a property binding is not updating when the appropriate C++ property notify signal is changed, despite a Connections object responding to the signal properly. For example:

TextEdit {
    id: descriptionEdit

    // `enabled` never changes
    enabled: eventModel.numDescriptionWritable > 0

    // But this one works. What gives?
    Connections {
        onNumDescriptionWritableChanged {
            print('numDescriptionWritableChanged():', eventModel.numDescriptionWritable)
        }
    }
}

What sort of conditions would make the possible?

J.Hilk

hi @patrickkidd

have you tried with parentheses ?

enabled: (eventModel.numDescriptionWritable > 0 )

and do you assign anywhere a bool to enabled, using = ? If yes, than that breaks all previous bindings.

patrickkidd

@J.Hilk said in Bindings not updating when property notify signal is emitted:

hi @patrickkidd

have you tried with parentheses ?

enabled: (eventModel.numDescriptionWritable > 0 )

and do you assign anywhere a bool to enabled, using = ? If yes, than that breaks all previous bindings.

Nope, haven't assigned bool anywhere else. Parenthesis doesn't seem to work.

J.Hilk

@patrickkidd
particular ...

what does the console log print here ?

TextEdit {
    id: descriptionEdit

    // `enabled` never changes
    enabled: eventModel.numDescriptionWritable > 0
    Component.onCompleted: console.log("descriptionEdit completed", eventModel.numDescriptionWritable, enabled)

patrickkidd

@J.Hilk said in Bindings not updating when property notify signal is emitted:

@patrickkidd
particular ...

what does the console log print here ?

TextEdit {
    id: descriptionEdit

    // `enabled` never changes
    enabled: eventModel.numDescriptionWritable > 0
    Component.onCompleted: console.log("descriptionEdit completed", eventModel.numDescriptionWritable, enabled)

It prints 0 and false, which are the correct values before the model is initialized and before the integer becomes nonzero. Though I think the Connections object is already accomplishing the purpose of that print statement. Therefore, setting ‘enabled’ explicitly from the connections object is a workout that works, though I’d like to fix the problem itself.