A simple Win32 C++ desktop application that can show WinUI3 elements

This is a regular Win32 desktop application which knows nothing about WinUI3, it's main message loop is completely standard. Click on "Show WinUI3 Window menu item" to add WinUI3 content to it:

This is what we'll see, the Click button is a WinUI3 button, using DesktopWindowXamlSource to connect to a C# .NET 8 WinUI3 component library:

Click on it and a WinUI3 ContentDialog is shown:

Note there's a way to keep Win32 style (XAML style not initialized) like this: