(Winui3/C++) How to correctly initialize the data of the window class (e.g., MainWindow).

C++ WinUI 3 examples are really scarce.
I need to initialize the following code:
sourceList().ItemsSource(sourceArray);

struct MainWindow : MainWindowT<MainWindow>
{
    MainWindow()
    {
        // Xaml objects should not call InitializeComponent during construction.
        // See https://github.com/microsoft/cppwinrt/tree/master/nuget#initializecomponent

       //When I initialize here, an error occurs. I think it's because the component is not fully initialized.
        sourceList().ItemsSource(sourceArray); 
    }
...

Where should I elegantly and right implement the initialization of this code?

Start with the MainWindow constructor and the referenced C++/WinRT InitializeComponent guidance. Determine the appropriate post-initialization point for sourceList().ItemsSource(sourceArray), then verify that the window initializes without the reported error.