qt-qml-id ReferenceError after setContextPropertiy

[make2]

MouseArea{
	anchors.fill: parent
	onClicked: {
		fileList.currentIndex = index
		mainView.openFile(modelData); // call C++ context->setContextPropertiy("", ""), 
		console.log(fileList) // error: ReferenceError: fileList is not defined
	}
}

how can i use id(fileList) after setContextPropertiy?

[make2]

let obj = tabView // save param before call setContextPropertiy
let tabName = name // save model item attr
fileList.currentIndex = index
mainView.openFile(modelData); // call C++ context->setContextPropertiy("", ""), 
console.log(obj) // res: qml: TabView_QMLTYPE_10(0x3c5a220)
obj.addTab(tabName)

i do this, it work, but I dont not know why?

[make2]

@make2 i refresh model of a ListView by setContextProperty

[make2]

let obj = tabView // save param before call setContextPropertiy
let tabName = name // save model item attr
fileList.currentIndex = index
mainView.openFile(modelData); // call C++ context->setContextPropertiy("", ""), 
console.log(obj) // res: qml: TabView_QMLTYPE_10(0x3c5a220)
obj.addTab(tabName)

i do this, it work, but I dont not know why?