WInUI 3.0 桌面 - 尝试导航时出现异常崩溃

Question

I want to change frame, but I get this exception:

Navigation:

Frame rootFrame = new Frame();
rootFrame.Navigate(typeof(ScoreWindow), null, new EntranceNavigationTransitionInfo());

Exception appears on constructor:

        public ScoreWindow()
        {
            this.InitializeComponent();
            results = new List<Result>();
            playerList = new();
            LoadData();
            var _resultsView = ConvertToView();
            sfDataGrid.ItemsSource = _resultsView;
        }

Thanks for answers in advance and happy holidays!

PS Thanks to Raymond, I detected this message:

WinUI: Error creating second Desktop Window on the current process. No more than one Desktop Window is allowed per process.

There is another question: how to change current frame to other? I mean, I have login view, user logged in successfully and want to see data/other things.

Answer 1

After a little break, I understood what I did wrong. There is a way how to navigate between pages.

Rule #1: In WinUI, you have only one active window, and it's MainWindow. Always. If you want to change layout, you have to use Frames.

In MainWindow.xaml, you write this:

    <Grid>
        <Frame x:Name="mainFrame"/>
    </Grid>

Element "Frame" give ability to navigate between pages.

Then switch to MainWindow.xaml.cs and in constructor have to be something like this:

        public MainWindow()
        {
            InitializeComponent();
            mainFrame.Navigate(typeof(NameOfYourPage));
        }

It will immediately activate your page.

Then, if you want to navigate from page to page, write in control of page this:

Frame.Navigate(typeof(NameOfYourPage), null, new EntranceNavigationTransitionInfo());

The third parameter is animation, but I didn't notice changes.

More information you can find here:

Tutorial about navigation

Microsoft documentation