Xamarin Forms Migration

What it does

When your agent uses it

• : migrate Xamarin.Forms
• Upgrade to MAUI
• Xamarin to MAUI
• Convert Xamarin.Forms project

Example prompts

• “migrate Xamarin.Forms”
• “upgrade to MAUI”
• “Xamarin to MAUI”
• “/xamarin-forms-migration”

Workflow steps

11 steps, taken from the first numbered list in SKILL.md.

1. 1Create new .NET MAUI project (single-project — multi-project causes AOT/build errors)
2. 2Copy cross-platform code + platform code into Platforms//
3. 3Update namespaces (XAML + C# + Essentials — see references/forms-migration-api.md)
4. 4Fix layout behavior changes (see below)
5. 5Migrate renderers → handlers (not shimmed renderers)
6. 6Migrate effects → behaviors
7. 7Remove Microsoft.Maui.Controls.Compatibility package
8. 8Update NuGet dependencies
9. 9Migrate app data stores
10. 10Delete bin//obj//Resource.designer.cs, build, test iteratively
11. 11Verify against .NET 10 deprecated API list

What it can do on your machine

Read from SKILL.md and the folder at commit 79bb4bf. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are xml and csharp).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Hosts in commands or code, which the agent is likely to contact:

  • schemas.microsoft.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Xamarin Forms Migration loads about 1.8k tokens when it runs, and up to ~3.8k if it reads all its reference files. Until then it costs about 247 tokens; SKILL.md has 621 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~247

When it runs · the whole SKILL.md, loaded when a task matches

~1.8k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~3.8k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from davidortinau/maui-skills at commit 79bb4bf, republished under its MIT licence (© davidortinau). 621 words, ~1,817 tokens.

name

xamarin-forms-migration

description

**WORKFLOW SKILL** - Guide for migrating Xamarin.Forms apps to .NET MAUI. Covers project structure decisions, SDK-style project conversion, namespace renames, layout behavior changes, renderer-to-handler migration, effects-to-behaviors redesign, Xamarin.Essentials namespace mapping, NuGet dependency compatibility, data migration, and common troubleshooting. Incorporates field-tested advice from production migrations. USE FOR: "migrate Xamarin.Forms", "upgrade to MAUI", "Xamarin to MAUI", "convert Xamarin.Forms project", "Forms migration", "namespace changes Xamarin", "renderer to handler", "effects to behaviors", "AndExpand replacement", "layout changes MAUI", "Xamarin.Essentials to MAUI". DO NOT USE FOR: migrating Xamarin.Android native apps (use xamarin-android-migration), migrating Xamarin.iOS native apps (use xamarin-ios-migration), creating new MAUI handlers from scratch (use maui-custom-handlers), performance optimization (use maui-performance).

<!-- ❌ Looks fine in Xamarin.Forms, cramped in MAUI -->
<Grid>...</Grid>
<StackLayout>...</StackLayout>

<!-- ✅ Add explicit values or restore via implicit styles in App.xaml -->
<Style TargetType="Grid">
    <Setter Property="ColumnSpacing" Value="6"/>
    <Setter Property="RowSpacing" Value="6"/>
</Style>

<!-- ❌ Silently ignored in MAUI — image won't expand -->
<StackLayout>
    <Label Text="Hello world!"/>
    <Image VerticalOptions="FillAndExpand" Source="dotnetbot.png"/>
</StackLayout>

<!-- ✅ Convert to Grid with star sizing -->
<Grid RowDefinitions="Auto, *">
    <Label Text="Hello world!"/>
    <Image Grid.Row="1" Source="dotnetbot.png"/>
</Grid>

// ✅ Extend existing handler — no new class needed
Microsoft.Maui.Handlers.EntryHandler.Mapper.AppendToMapping("NoBorder", (handler, view) =>
{
#if ANDROID
    handler.PlatformView.Background = null;
#elif IOS || MACCATALYST
    handler.PlatformView.BorderStyle = UIKit.UITextBorderStyle.None;
#endif
});

© davidortinau, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in plugins/maui-skills/skills/xamarin-forms-migration of davidortinau/maui-skills.

• SKILL.md
• references/forms-migration-api.md

Open the folder on GitHubat commit 79bb4bf