Update Mica XAML and C# samples

[Jay-o-Way]

Issue type

enhancement

Which version of the app?

WinUI 3 Gallery

Description

Now that Mica is in W.A.SDK 1.3, we should mention the xaml on the Backdrops page. And/or link to https://learn.microsoft.com/windows/windows-app-sdk/api/winrt/microsoft.ui.xaml.media.micabackdrop

Screenshots

[niels9001]

@Jay-o-Way @karkarl Should we remove the existing sample code altogether and just show the one line XAML / C# strings? Not really a point to show complicated/verbose code if 1.3 introduces an easy way to do things 😊? (Might convince devs to adopt it as it's just so easy now!)

[Jay-o-Way]

Sounds perfect!

[LoganDark]

@Jay-o-Way @karkarl Should we remove the existing sample code altogether and just show the one line XAML / C# strings? Not really a point to show complicated/verbose code if 1.3 introduces an easy way to do things 😊? (Might convince devs to adopt it as it's just so easy now!)

Absolutely, it took me a while to discover the easy way. Just need to make it explicit that Visual Studio projects don't use version 1.3 of the SDK by default, and you have to manually upgrade the NuGet package after creating the project (then change the run configuration or else it'll say something about CompileXaml not supporting PrecompiledHeaderFiles which is a false positive)