Change property value without destroying binding to support two-way binding - qt

Question

I want to create a custom component, which allows two-way binding with the following (traditional) setup:
// main.qml
property var someStoredValue: someInitialValue // may be C++ property in real application
MyCustomComponent
{
myProperty: someStoredValue // this binding will be destroyed on user input
onMyPropertyChanged: someStoredValue = myProperty
}
// MyCustomComponent.qml
Item
{
property var myProperty: null
MouseArea
{
anchors.fill: parent
onClicked: myProperty = "some text or other value" // breaks the binding set in main.cpp
}
}
MyCustomComponent should be able to update myProperty (programmatically), without destroying the binding between someStoredValue and myProperty. How can I change the implementation of MyCustomComponent to achieve my goal?

Answer 1

One solution would be to use a Binding object to update myProperty inside MyCustomComponent, instead of directly changing the value:
// MyCustomComponent.qml
Item
{
property var myProperty: null
Binding on myProperty
{
id: myPropertyUpdater
function set(newValue) {value = newValue; when = true; when = false;}
when: false
}
MouseArea
{
anchors.fill: parent
onClicked: myPropertyUpdater.set("some text or other value")
}
}
The trick is to shortly set the when property of Binding to true, to propagate the new value. After inactivating the Binding (when = false;), any previous direct binding will be restored, as stated in the docs:
When the binding becomes inactive again, any direct bindings that were
previously set on the property will be restored.