davidortinau/maui-skills/maui-current-apis

.NET MAUI Current APIs — Guardrail Skill

This skill prevents you from generating code that uses deprecated, obsolete, or removed APIs. Read this before writing any .NET MAUI, Blazor Hybrid, or MauiReactor code.

Reasoning Framework

Follow these steps before generating any MAUI-related code:

Step 1 — Detect the Target Framework

Read the project's .csproj file and find <TargetFramework> or <TargetFrameworks>:

<!-- Single target -->
<TargetFramework>net10.0-android</TargetFramework>
 
<!-- Multi-target (typical MAUI project) -->
<TargetFrameworks>net10.0-android;net10.0-ios;net10.0-maccatalyst;net10.0-windows10.0.19041.0</TargetFrameworks>

The version number (net10.0, net9.0, net8.0) determines which APIs are available. Always target the version in the project file — never assume a version.

Step 2 — Detect Library Versions

Scan <PackageReference> entries and <ItemGroup> for key packages:

If no explicit MAUI package version is listed, the MAUI SDK version matches the <TargetFramework> .NET version.

Step 3 — Verify API Currency

Before using any API, ask yourself:

1. Does this API exist in the detected version? If you're unsure, prefer the newer pattern.
2. Is this a Xamarin.Forms API? MAUI is a different API surface — never assume Xamarin.Forms compatibility.
3. Is this in the deprecated table below? If so, use the replacement.
4. Am I using the Compatibility namespace? Microsoft.Maui.Controls.Compatibility.* types are migration aids, not recommended for new code.

Step 4 — Apply Decision Rules

• Always use the newest form of an API when both old and new exist.
• Never generate `using Xamarin.Forms` or using Xamarin.Essentials — these are not MAUI.
• Never use the `Compatibility` namespace in new projects (Compatibility.RelativeLayout, Compatibility.StackLayout, etc.).
• Prefer `async` method names when both sync-named and async-named versions exist (e.g., DisplayAlertAsync over DisplayAlert).
• Check the project's NuGet versions before using CommunityToolkit or third-party APIs.

Deprecated API Table — .NET MAUI 10

Controls

Gestures & Input

Page & Navigation

Animation

Device & Platform APIs

XAML & Markup

Safe Area & Layout

Accessibility

NuGet Packages

MauiReactor-Specific Guidance

MauiReactor v3+ (for .NET MAUI 9/10):

• Hot reload: v3+ uses a feature switch in .csproj via <RuntimeHostConfigurationOption>. Do NOT use the v2 EnableMauiReactorHotReload() call in MauiProgram.cs.
• API wrappers: MauiReactor auto-generates C# wrappers around MAUI controls. When a MAUI control is deprecated (e.g., ListView), the MauiReactor wrapper is also effectively deprecated. Use the MauiReactor wrapper for the replacement control (e.g., CollectionView).
• State management: Use State<T> and Props<T> — not older RxComponent patterns if they appear in outdated examples.
• Navigation: Use MauiReactor's built-in navigation (Navigation.PushAsync<PageComponent>()) — do NOT mix in MAUI Shell GoToAsync unless deliberately integrating Shell.

Blazor Hybrid-Specific Guidance

• Use `BlazorWebView` — not the legacy WebView — for hosting Razor components.
• Use .NET 10 Razor syntax: @rendermode directives, [SupplyParameterFromQuery], and the latest component model.
• JS interop: Use IJSRuntime.InvokeAsync<T>() — not the obsolete synchronous IJSInProcessRuntime patterns for mobile.
• Safe areas: In Blazor Hybrid, use CSS env(safe-area-inset-*) — do NOT combine XAML SafeAreaEdges and CSS safe area padding on the same element (causes double-padding).
• Web resource interception: .NET 10 adds WebResourceRequested event on BlazorWebView and HybridWebView for intercepting requests.

Version Detection Cheat Sheet

Reading the TFM

Reading MAUI SDK Version

If the .csproj uses <UseMaui>true</UseMaui>, the MAUI version matches the TFM:

• net10.0 → MAUI 10
• net9.0 → MAUI 9

Reading MauiReactor Version

Check <PackageReference Include="Reactor.Maui" Version="X.Y.Z" />:

• v3.x → .NET MAUI 9/10 compatible, uses feature-switch hot reload
• v2.x → Legacy, uses EnableMauiReactorHotReload() builder pattern

Reading CommunityToolkit Version

Check <PackageReference Include="CommunityToolkit.Maui" Version="X.Y.Z" />:

• v11+ → .NET 10 compatible
• v9-10 → .NET 9 compatible
• v5-7 → .NET 8 compatible

Quick Rules

1. Read the `.csproj` first. Never generate code without knowing the target framework.
2. When in doubt, use the newer API. If two ways exist to do something, the newer way is correct.
3. Never use `Xamarin.*` namespaces. They do not exist in MAUI.
4. Never use `Compatibility.*` types in new projects. They are migration aids only.
5. Check this table before using any `Device.*` API. The Device class is fully deprecated.
6. Use `*Async` method names for animations, alerts, and action sheets in .NET 10+.
7. Verify third-party package versions before using their APIs — CommunityToolkit, MauiReactor, and others break between major versions.