winui

# WinUI 3 and Windows App SDK ## Trigger On - building native modern Windows desktop UI on WinUI 3 - integrating Windows App SDK features into a .NET app - deciding between WinUI, WPF, WinForms, and MAUI for Windows work - implementing MVVM patterns in Windows App SDK applications ## Workflow 1. **Confirm WinUI is the right choice** — use when modern Windows-native UI, Fluent Design, and Windows App SDK capabilities are needed. For cross-platform, consider MAUI instead. 2. **Choose packaging model early** — packaged (MSIX) vs unpackaged differ materially for deployment, identity, and API access: ```xml <!-- Unpackaged: add to .csproj --> <WindowsPackageType>None</WindowsPackageType> ``` 3. **Apply MVVM pattern** with the MVVM Toolkit — keep views dumb, logic in ViewModels: ```csharp public partial class ProductsViewModel : ObservableObject { [ObservableProperty] private ObservableCollection<Product> _products = []; [ObservableProperty] [NotifyCanExecuteChangedFor(nameof(DeleteCommand))] private Product? _selectedProduct; [RelayCommand(CanExecute = nameof(CanDelete))] private async Task DeleteAsync() { if (SelectedProduct is null) return; await _productService.DeleteAsync(SelectedProduct.Id); Products.Remove(SelectedProduct); } private bool CanDelete() => SelectedProduct is not null; } ``` 4. **Use x:Bind for compiled bindings** — better perfo...