/maui

name: maui
description: "Build, review, or migrate .NET MAUI applications across Android, iOS, macOS, and Windows with correct cross-platform UI, platform integration, and native packaging assumptions. USE FOR: working on cross-platform mobile or desktop UI in .NET MAUI; integrating device capabilities, navigation, or platform-specific code; migrating Xamarin.Forms or aligning. DO NOT USE FOR: unrelated stacks; generic tasks that do not need this specific guidance. INVOKES: inspect the repository context, edit targeted files, and run relevant build, test, lint, or validation commands when changes are made."
compatibility: "Requires .NET MAUI workload (.NET 8+)."

.NET MAUI

Trigger On

• working on cross-platform mobile or desktop UI in .NET MAUI
• integrating device capabilities, navigation, or platform-specific code
• migrating Xamarin.Forms or aligning a shared codebase across targets
• implementing MVVM patterns in mobile apps

Documentation

• [.NET MAUI Overview](https://learn.microsoft.com/en-us/dotnet/maui/what-is-maui)
• [Enterprise Patterns](https://learn.microsoft.com/en-us/dotnet/architecture/maui/)
• [MVVM Pattern](https://learn.microsoft.com/en-us/dotnet/architecture/maui/mvvm)
• [Controls Reference](https://learn.microsoft.com/en-us/dotnet/maui/user-interface/controls/)
• [Platform Integration](https://learn.microsoft.com/en-us/dotnet/maui/platform-integration/)

References

• [patterns.md](references/patterns.md) - Shell navigation, platform-specific code, messaging, lifecycle, data binding, and CollectionView patterns
• [anti-patterns.md](references/anti-patterns.md) - Common MAUI mistakes and how to avoid them

Platform Targets

| Platform | Build Host | Notes | |----------|------------|-------| | Android | Windows/Mac | Emulator or device | | iOS | Mac only | Requires Xcode | | macOS | Mac only | Catalyst | | Windows | Windows | WinUI 3 |

Workflow

1. **Confirm target platforms** — behavior differs across Android, iOS, Mac, Windows 2. **Separate shared UI and platform code** — use handlers and DI 3. **Follow MVVM pattern** — keep views dumb, logic in ViewModels 4. **Handle lifecycle and permissions** — platform contracts need testing 5. **Test on real devices** — emulators don't catch everything

Current Upstream Notes

• `.NET MAUI` `10.0.90` is a broad quality release for the 10.0 line. It fixes grouped `CollectionView` scrolling, layout, selection, and retention paths; Android `BlazorWebView` back handling; WebView rendering and lifecycle leaks; Shell/navigation regressions; and several shared-resource, handler, map, SafeArea, and accessibility issues.
• After upgrading MAUI packages, smoke-test grouped and virtualized `CollectionView` flows, Shell/modal/back navigation, tabs, keyboard and SafeArea interactions, maps, WebView/HybridWebView lifecycle, memory retention, and accessibility narration on every shipped target.
• The July 2026 `.NET MAUI` Learn overview for `net-maui-10.0` still frames the platform around a shared single-project app, native API access, handlers, and optional Blazor Hybrid UI. Verify each target platform rather than treating shared code as identical runtime behavior.

Project Structure

MyApp/
├── MyApp/                    # Shared code
│   ├── App.xaml              # Application entry
│   ├── MauiProgram.cs        # DI and configuration
│   ├── Views/                # XAML pages
│   ├── ViewModels/           # MVVM ViewModels
│   ├── Models/               # Domain models
│   ├── Services/             # Business logic
│   └── Platforms/            # Platform-specific code
│       ├── Android/
│       ├── iOS/
│       ├── MacCatalyst/
│       └── Windows/
└── MyApp.Tests/

MVVM Pattern

ViewModel with MVVM Toolkit

public partial class ProductsViewModel(IProductService productService) : ObservableObject
{
    [ObservableProperty]
    private ObservableCollection<Product> _products = [];

    [ObservableProperty]
    [NotifyCanExecuteChangedFor(nameof(LoadProductsCommand))]
    private bool _isLoading;

    [RelayCommand(CanExecute = nameof(CanLoadProducts))]
    private async Task LoadProductsAsync()
    {
        IsLoading = true;
        try
        {
            var items = await productService.GetAllAsync();
            Products = new ObservableCollection<Product>(items);
        }
        finally
        {
            IsLoading = false;
        }
    }

    private bool CanLoadProducts() => !IsLoading;
}

View Binding

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:vm="clr-namespace:MyApp.ViewModels"
             x:Class="MyApp.Views.ProductsPage"
             x:DataType="vm:ProductsViewModel">

    <RefreshView Command="{Binding LoadProductsCommand}"
                 IsRefreshing="{Binding IsLoading}">
        <CollectionView ItemsSource="{Binding Products}">
            <CollectionView.ItemTemplate>
                <DataTemplate x:DataType="models:Product">
                    <VerticalStackLayout Padding="10">
                        <Label Text="{Binding Name}" FontSize="18" />
                        <Label Text="{Binding Price, StringFormat='{0:C}'}" />
                    </VerticalStackLayout>
                </DataTemplate>
            </CollectionView.ItemTemplate>
        </CollectionView>
    </RefreshView>
</ContentPage>

Dependency Injection

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder
            .UseMauiApp<App>()
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
            });

        // Services
        builder.Services.AddSingleton<IProductService, ProductService>();
        builder.Services.AddSingleton<INavigationService, NavigationService>();