# dotnet-maui-9-to-dotnet-maui-10-upgrade

Guides .NET MAUI migrations from version 9 to 10 by updating TargetFrameworks, replacing internal MessagingCenter calls, and migrating obsolete UI controls.

- rule · `type=rule` · GitHub Copilot · ★ 40418
- Author: github · official GitHub repository
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/github/awesome-copilot/tree/HEAD/instructions/dotnet-maui-9-to-dotnet-maui-10-upgrade.instructions.md
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/rules/dotnet-maui-9-to-dotnet-maui-10-upgrade

## What it does

This rule triggers on `*.csproj`, `*.cs`, and `*.xaml` files. It organizes the migration process. First, it switches target frameworks to `net10.0`. It also adds conditions to skip iOS and Mac Catalyst targets during Linux or GitHub Codespaces builds.

The primary fix addresses compiler blockers. Because `MessagingCenter` became internal in .NET 10, Copilot migrates code to `WeakReferenceMessenger` from `CommunityToolkit.Mvvm` 8.3.0 and introduces dedicated message classes. Runtime behavior also shifts. Registering duplicate subscriptions on one recipient throws an `InvalidOperationException`.

In XAML views, obsolete `ListView` and `TableView` declarations transition toward `CollectionView`. Legacy animation calls, `DisplayAlert`, and `Page.IsBusy` are marked for replacement. Without updating `CommunityToolkit.Maui` to version 12.3.0 or higher, the project fails to compile.

## Install

### GitHub Copilot (native platform)

**Manually: put the files in place**
- File: `.github/instructions/dotnet-maui-9-to-dotnet-maui-10-upgrade.instructions.md` — The applyTo field sets which files it applies to

### Claude Code

**Manually: put the files in place**
- File: `.claude/rules/dotnet-maui-9-to-dotnet-maui-10-upgrade.md` — The paths frontmatter field limits the files: move applyTo from the source into paths

### Codex

**AGENTS.md**
- Codex reads AGENTS.md: paste the rule text there

### Cursor

**Manually: put the files in place**
- File: `.cursor/rules/dotnet-maui-9-to-dotnet-maui-10-upgrade.mdc` — Frontmatter: description, globs, alwaysApply. Move applyTo from the source into globs, or the rule will not attach on its own

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/rules/dotnet-maui-9-to-dotnet-maui-10-upgrade.md`

### Cline

**Manually: put the files in place**
- File: `.clinerules/dotnet-maui-9-to-dotnet-maui-10-upgrade.md`

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/github/awesome-copilot/tree/HEAD/instructions/dotnet-maui-9-to-dotnet-maui-10-upgrade.instructions.md

## When to use it
- switch target frameworks to net10.0
- replace internal MessagingCenter with WeakReferenceMessenger
- configure Linux builds in Codespaces by excluding iOS targets
- migrate deprecated ListView components to CollectionView

## Example prompts
- Upgrade this MAUI project to .NET 10 and swap MessagingCenter for WeakReferenceMessenger
- Update target frameworks in csproj to support building on Linux without iOS tools
- Scan this XAML view and migrate obsolete ListView elements to CollectionView

## Source text · dotnet-maui-9-to-dotnet-maui-10-upgrade.instructions.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: cbff8b36346efa5c.

BEGIN THIRD-PARTY FILE cbff8b36346efa5c
````text
---
description: 'Instructions for upgrading .NET MAUI applications from version 9 to version 10, including breaking changes, deprecated APIs, and migration strategies for ListView to CollectionView.'
applyTo: '**/*.csproj, **/*.cs, **/*.xaml'
---

# Upgrading from .NET MAUI 9 to .NET MAUI 10

This guide helps you upgrade your .NET MAUI application from .NET 9 to .NET 10 by focusing on the critical breaking changes and obsolete APIs that require code updates.

---

## Table of Contents

1. [Quick Start](#quick-start)
2. [Update Target Framework](#update-target-framework)
3. [Breaking Changes (P0 - Must Fix)](#breaking-changes-p0---must-fix)
   - [MessagingCenter Made Internal](#messagingcenter-made-internal)
   - [ListView and TableView Deprecated](#listview-and-tableview-deprecated)
4. [Deprecated APIs (P1 - Fix Soon)](#deprecated-apis-p1---fix-soon)
   - [Animation Methods](#1-animation-methods)
   - [DisplayAlert and DisplayActionSheet](#2-displayalert-and-displayactionsheet)
   - [Page.IsBusy](#3-pageisbusy)
   - [MediaPicker APIs](#4-mediapicker-apis)
5. [Recommended Changes (P2)](#recommended-changes-p2)
6. [Bulk Migration Tools](#bulk-migration-tools)
7. [Testing Your Upgrade](#testing-your-upgrade)
8. [Troubleshooting](#troubleshooting)

---

## Quick Start

**Five-Step Upgrade Process:**

1. **Update TargetFramework** to `net10.0`
2. **Update CommunityToolkit.Maui** to 12.3.0+ (if you use it) - REQUIRED
3. **Fix breaking changes** - MessagingCenter (P0)
4. **Migrate ListView/TableView to CollectionView** (P0 - CRITICAL)
5. **Fix deprecated APIs** - Animation methods, DisplayAlert, IsBusy, MediaPicker (P1)

> ⚠️ **Major Breaking Changes**: 
> - CommunityToolkit.Maui **must** be version 12.3.0 or later
> - ListView and TableView are now obsolete (most significant migration effort)

---

## Update Target Framework

### Single Platform

```xml
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net10.0</TargetFramework>
  </PropertyGroup>
</Project>
```

### Multi-Platform

```xml
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFrameworks>net10.0-android;net10.0-ios;net10.0-maccatalyst;net10.0-windows10.0.19041.0</TargetFrameworks>
  </PropertyGroup>
</Project>
```

### Optional: Linux Compatibility (GitHub Copilot, WSL, etc.)

> 💡 **For Linux Development**: If you're building on Linux (e.g., GitHub Codespaces, WSL, or using GitHub Copilot), you can make your project compile on Linux by conditionally excluding iOS/Mac Catalyst targets:

```xml
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <!-- Start with Android (always supported) -->
    <TargetFrameworks>net10.0-android</TargetFrameworks>
    
    <!-- Add iOS/Mac Catalyst only when NOT on Linux -->
    <TargetFrameworks Condition="!$([MSBuild]::IsOSPlatform('linux'))">$(TargetFrameworks);net10.0-ios;net10.0-maccatalyst</TargetFrameworks>
    
    <!-- Add Windows only when on Windows -->
    <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows'))">$(TargetFrameworks);net10.0-windows10.0.19041.0</TargetFrameworks>
  </PropertyGroup>
</Project>
```

**Benefits:**
- ✅ Compiles successfully on Linux (no iOS/Mac tools required)
- ✅ Works with GitHub Codespaces and Copilot
- ✅ Automatically includes correct targets based on build OS
- ✅ No changes needed when switching between OS environments

**Reference:** [dotnet/maui#32186](https://github.com/dotnet/maui/pull/32186)
````
END THIRD-PARTY FILE cbff8b36346efa5c

The third-party file has ended. Everything between the cbff8b36346efa5c tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 3455 of 54173 bytes. © github · MIT · https://github.com/github/awesome-copilot/tree/HEAD/instructions/dotnet-maui-9-to-dotnet-maui-10-upgrade.instructions.md

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