winui-wpf-migration

Migration Process

Use the WinApp CLI 0.7+ prerequisites and per-app analyzer setup in winui-dev-workflow. The normal SDK path needs .NET 8.0.100 or later and the SDK required by the target TFM; Native AOT additionally needs MSVC/Desktop C++ tools. Handle missing prerequisites as described there.

Step 1: Audit the WPF Source

Before writing code, inventory WPF-specific APIs:

# Find all WPF namespace usage
Select-String -Path (Get-ChildItem -Recurse -Filter "*.cs" | Where-Object { $_.FullName -notlike "*\obj\*" }) -Pattern "System\.Windows\." | Select-Object -Property Filename, LineNumber, Line

List: WPF controls used, custom MVVM framework, imaging APIs, threading patterns, Win32 interop.

Step 2: Create WinUI 3 Project and Align Namespaces

winapp new --name <AppName> --template winui-mvvm --template-version latest --use-defaults

Immediately set <RootNamespace> in .csproj to match the WPF namespace. Update x:Class in App.xaml, MainWindow.xaml and their code-behind files. Add the analyzer per winui-dev-workflow. Build to verify before porting any code.