Window doesn't maximize in WinUI3

Question

I am using the following code to start a WinUI3 App maximized:

    public MainWindow()
    {
        this.InitializeComponent();
        var windowHandle = WinRT.Interop.WindowNative.GetWindowHandle(this);
        var windowId = Win32Interop.GetWindowIdFromWindow(windowHandle);
        AppWindow appWindow = AppWindow.GetFromWindowId(windowId);
        OverlappedPresenter presenter = (OverlappedPresenter)appWindow.Presenter;
        presenter.Maximize();
        Debug.WriteLine(presenter.State);
    }

There are no errors, debug output reports the OverlappedPresenter state as Maximized, but the window stays in the restored state.

Any suggestions are welcome, thanks in advance.

Answer 1

Try putting Maximize() in App's OnLaunched method:

    protected override void OnLaunched(LaunchActivatedEventArgs args)
    {
        ...
        presenter.Maximize();
    }

Or the Window's OnActivated event:

    private void OnActivated(object sender, WindowActivatedEventArgs args)
    {
        ...
        presenter.Maximize();
    }