Use this skill before changing MAUI app code when API currency matters. The goal is to inspect the project target first, then select APIs that match that target instead of generating stale Xamarin.Forms or early MAUI patterns.
Workflow
-
Inspect the target frameworks and package versions before recommending APIs:
grep -R -n --include="*.csproj" --include="Directory.Build.props" "<TargetFramework" . 2>/dev/null grep -R -n --include="*.csproj" --include="Directory.Build.props" --include="Directory.Packages.props" \ "Microsoft.Maui.Controls\\|UseMaui\\|MauiVersion" . 2>/dev/null
- Identify whether the project targets .NET 8, .NET 9, .NET 10, or multiple
versions. Do not assume
net10.0. - Prefer APIs from
Microsoft.Maui.*namespaces. Do not addXamarin.FormsorXamarin.Essentialsnamespaces to MAUI projects. - If replacing an obsolete API, explain the replacement and why it matches the detected target.
- Keep platform-specific code behind
#if ANDROID,#if IOS,#if MACCATALYST,#if WINDOWS, or an injected platform service. - Build the changed project for the relevant target framework.
Common Agent Traps
| Avoid | Prefer |
|---|---|
using Xamarin.Forms; |
using Microsoft.Maui.Controls; |
using Xamarin.Essentials; |
using Microsoft.Maui.ApplicationModel, Microsoft.Maui.Devices, Microsoft.Maui.Storage, or the specific MAUI namespace |
Device.BeginInvokeOnMainThread(...) |
MainThread.BeginInvokeOnMainThread(...) |
Device.StartTimer(...) |
Dispatcher.StartTimer(...) or IDispatcherTimer |
Device.RuntimePlatform for platform behavior |
DeviceInfo.Platform, OnPlatform, or compile-time platform services |
MessagingCenter for new app architecture |
WeakReferenceMessenger, events, interfaces, or another explicit messaging abstraction |
| Old Xamarin.Forms custom renderers for new code | MAUI handlers, property mappers, or platform services |
| Hard-coded safe area padding | SafeAreaEdges / safe area APIs for the detected MAUI version |
| Coordinate-based UI automation | Stable AutomationId plus DevFlow queries |
Application.Current.MainPage = ... for routine navigation |
Shell navigation with registered routes, or set Window.Page explicitly for intentional app reset flows |
Safe Area Guidance
For .NET 10+ safe area work, prefer SafeAreaEdges over legacy iOS-only safe
area patterns. Confirm the target framework before changing safe area code:
<Grid SafeAreaEdges="Container">
...
</Grid>
Use platform-specific fallbacks only when the app targets an older MAUI version where the newer API is unavailable.
Window and Shell Guidance
- In multi-window code, do not blindly rely on a global main page. Use the
current
Window,Shell.Current, or an injected navigation abstraction that matches the app's architecture. - For Shell apps, use registered routes and
GoToAsyncinstead of manually replacing root pages unless the app intentionally owns the full window flow. - For navigation parameters, prefer
IQueryAttributableor[QueryProperty]and URL-encode route values when building URI strings.
Validation Checklist
- The edited project target framework was inspected.
- No
Xamarin.FormsorXamarin.Essentialsnamespace was introduced. - Replacements are compatible with the detected MAUI version.
- Platform-specific code is isolated behind target-specific files, partial
classes, DI abstractions, or
#ifguards. - The changed target framework builds.