Hey there! No worries at all—everyone starts somewhere with WinUI, so don’t stress about being a beginner. Let’s break down your questions one by one:

1. Transparent Main Window for Shaped Windows in WinUI 3 (Windows App SDK) #

Absolutely, you can achieve a transparent window for shaped UIs in WinUI 3, though the approach is a bit different from WPF. Here’s how:

• First, disable the window border and title bar: You’ll need to use the AppWindow API to modify the window presenter. In your code-behind (e.g., MainWindow.xaml.cs), add this logic (usually in the constructor):

  using Microsoft.UI.Windowing;
  using Microsoft.UI.Xaml;
  
  public MainWindow()
  {
      this.InitializeComponent();
      var appWindow = GetAppWindowForCurrentWindow();
      if (appWindow != null)
      {
          var overlappedPresenter = appWindow.Presenter as OverlappedPresenter;
          if (overlappedPresenter != null)
          {
              // Disable border and title bar
              overlappedPresenter.IsBorderEnabled = false;
              overlappedPresenter.SetBorderAndTitleBar(false, false);
          }
      }
  }
  
  // Helper method to get the AppWindow for the current XAML Window
  private AppWindow GetAppWindowForCurrentWindow()
  {
      var hWnd = WinRT.Interop.WindowNative.GetWindowHandle(this);
      var windowId = Microsoft.UI.Win32Interop.GetWindowIdFromWindow(hWnd);
      return AppWindow.GetFromWindowId(windowId);
  }
  

• Set the window background to transparent: In your MainWindow.xaml, set the Window element’s Background to Transparent:

  <Window
      x:Class="YourAppNamespace.MainWindow"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      Background="Transparent">
      <!-- Your UI content here -->
  </Window>
  

• Create shaped UI: To make an irregular window, use the Clip property on your root container (like a Grid or Border) to define the shape you want. For example, a circular window could use an EllipseGeometry as the clip.

2. Windows 11-Style Window Rounded Corners on Windows 10 #

Windows 11’s rounded window corners are a system-level feature that Windows 10 doesn’t natively support. However, you can simulate this effect in WinUI 3 on Windows 10:

• Hide the default window border: Use the same AppWindow logic from the first question to disable the border.
• Add a rounded container: Wrap your entire UI in a Border with a CornerRadius set to match Windows 11’s typical 16px radius, and set a solid background. Your XAML would look something like this:

  <Window Background="Transparent">
      <Grid>
          <Border CornerRadius="16" Background="White" Padding="10">
              <!-- Your main UI content goes here -->
          </Border>
      </Grid>
  </Window>
  

This creates the illusion of a rounded window since the transparent outer window hides behind the rounded border. Note this is a custom implementation, not the native system-rounded corners from Windows 11.

3. Mica Material Support on Windows 10 #

Unfortunately, Mica is exclusive to Windows 11 and later versions. The Mica brush APIs are part of the Windows 11 SDK and won’t work on Windows 10.

If you want a similar blurred background effect on Windows 10, you can use the AcrylicBrush (available on Windows 10 1809 and above). Acrylic provides a semi-transparent, blurred background, though it’s not the same as Mica’s more subtle, static appearance.

内容的提问来源于stack exchange，提问作者AlexPalex