WPF to WinUI 3 Migration Skill

Migrate PowerToys modules from WPF (System.Windows.*) to WinUI 3 (Microsoft.UI.Xaml.* / Windows App SDK). Based on patterns validated in the ImageResizer module migration.

When to Use This Skill

• Migrate a PowerToys module from WPF to WinUI 3
• Convert WPF XAML files to WinUI 3 XAML
• Replace System.Windows namespaces with Microsoft.UI.Xaml
• Migrate Dispatcher usage to DispatcherQueue
• Migrate custom Observable/RelayCommand to CommunityToolkit.Mvvm source generators
• Replace WPF-UI (Lepo) controls with native WinUI 3 controls
• Convert imaging code from System.Windows.Media.Imaging to Windows.Graphics.Imaging
• Handle WPF Window vs WinUI Window differences (sizing, positioning, SizeToContent)
• Migrate resource files from .resx to .resw with ResourceLoader
• Fix installer/build pipeline issues after WinUI 3 migration
• Update project files, NuGet packages, and signing config

Prerequisites