WinUI3 : Managing lifecycle of widget in c++

Question

Hi,

I'm working on WinUI3 Desktop app in c++. I'm not using XAML in any part of my code. All the widget creation happens programmatically in c++.

After I create a widget ill store that widget in this IObservableMap

IObservableMap<int, UIElement> gIdMap = single_threaded_observable_map<int, UIElement>();

Like this

void  CreateText ()
{
	StackPanel parent = GetTopContainer ();  // return WinUI3 StackPanel element, which was already visible on screen

	TextBox text;

	text.Text(L"Samnple);

	parent.Childern().Append(text);

    gIdMap.Insert(gNumericID, text.as<UIElement>());

}

Later when I remove the TextBox from parent StackPanel with StackPanel.Children().RemoveAt(index), the TextBox reference in gIdMap will still be there. i,e that wont get destructed

I can understand as everything here is smart pointer, object wont be destructed till the reference count is 0.

My doubt is, how will I clear the TextBox object stored in gIdMap (IObservableMap). Will gIdMap.Remove() clear the memory allocated for the TextBox , Will the TextBox be distructed?

Thank you

Answer 1

Yes, It will. I have tested and also see WinUI-Gallery.

    MainWindow::MainWindow()
        :m_bookSkus(winrt::single_threaded_observable_vector<IInspectable>())
       //, gIdMap(single_threaded_observable_map<int, Microsoft::UI::Xaml::IUIElement>())
       , gIdMap(single_threaded_observable_map<int, IInspectable>())
    {
        InitializeComponent();
        App1::BookSku p = make<winrt::App1::implementation::BookSku>();
        gIdMap.Insert(1, p);
    }

    void MainWindow::myButton_Click(IInspectable const& a, RoutedEventArgs const&)
    {
        myButton().Content(box_value(L"Clicked"));
        gIdMap.Remove(1);
	}