Mica material not showing up on secondary window-CodePudding

I have a little problem with a multi-window UWP app.

I have the Mica material applied to my page and when I run my program, the first window shows with the Mica material. If I click on show second window, It pops up, but the background is in my system-accent-color, not the Mica material.

Here my code of MainPage.xaml:

<Page
    x:Class="MultiWindowTest.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:MultiWindowTest"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:muxc="using:Microsoft.UI.Xaml.Controls"
    muxc:BackdropMaterial.ApplyToRootOrPageBackground="True">

    <Grid>
        <Button Click="Button_Click" Content="New Window" HorizontalAlignment="Center" VerticalAlignment="Center"/>
    </Grid>
</Page>

MainPage.xaml.cs:

private async void Button_Click(object sender, RoutedEventArgs e)
{
    AppWindow appWindow = await AppWindow.TryCreateAsync();
    Frame appWindowContentFrame = new Frame();
    appWindowContentFrame.Navigate(typeof(MainPage));
    ElementCompositionPreview.SetAppWindowContent(appWindow, appWindowContentFrame);

    await appWindow.TryShowAsync();
}

Here is also an image, as you can see the first window has the Mica material and the second one is only colored in my Accent color:

Can someone explain this phenomenon? Or did I do something wrong? Or is it a bug from Microsoft?

CodePudding user response：

Mica material not showing up on secondary window

It looks BackdropMaterial is not compatible with AppWindow, please go ahead post this in WinUI github, and currently there is a workaround that use ApplicationView to implement multiple views. And ApplicationView could show BackdropMaterial correctly in the second view.

CoreApplicationView newView = CoreApplication.CreateNewView();
int newViewId = 0;
await newView.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
    Frame frame = new Frame();
    frame.Navigate(typeof(MainPage), null);
    Window.Current.Content = frame;
    // You have to activate the window in order to show it later.
    Window.Current.Activate();

    newViewId = ApplicationView.GetForCurrentView().Id;
});
bool viewShown = await ApplicationViewSwitcher.TryShowAsStandaloneAsync(newViewId);

For more detail, please refer to document here.