esolve MAUI XAML source generator error with nested markup extensions

[IsmailHassani]

The Release mode build was failing with error MAUIG1001: "Value cannot be null. (Parameter 'key')" on iOS, Android, and macCatalyst platforms.

Root cause: The MAUI XAML source generator cannot parse nested markup extensions when a custom markup extension ({m:GetString}) is used inside another markup extension ({OnPlatform}).

Fix: Changed the RefreshButtonStyle's Text property from inline nested syntax:
Value="{OnPlatform WinUI={m:GetString Refresh}}"

To expanded element syntax:

This allows the source generator to properly parse and defer the custom markup extension evaluation to runtime.

Summary by CodeRabbit

• Style
  • Updated internal styling structure for improved consistency and maintainability.

Note: This release contains no user-facing changes.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[Copilot]

Pull request overview

This PR resolves a MAUI XAML source generator error (MAUIG1001) that occurred during Release mode builds on iOS, Android, and macCatalyst platforms. The error was caused by nested markup extensions in the RefreshButtonStyle where a custom markup extension was used inside an OnPlatform markup extension.

Key Changes:

• Converted inline nested markup extension syntax to expanded element syntax for the RefreshButtonStyle's Text property
• This change enables proper parsing by the MAUI XAML source generator while maintaining identical runtime functionality

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Walkthrough

A XAML style definition was modified in the RefreshButtonStyle to restructure how the Text setter's platform-specific value is defined. The OnPlatform expression was moved from directly within the Value attribute to an explicit OnPlatform element nested inside a Setter.Value block, altering the XML structure without changing functional behavior.

Changes

Cohort / File(s)	Summary
RefreshButtonStyle restructuring samples/Sample.Maui/Resources/Styles/Style.xaml	Modified Text setter definition from direct OnPlatform expression to explicit Setter.Value wrapping with nested OnPlatform element

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

• Verify XAML syntax correctness and proper nesting of OnPlatform element
• Confirm the style compiles and applies the intended platform-specific text values
• Check that the restructured setter maintains functional equivalence across iOS and Android platforms

Poem

🐰 Hops through XAML files with care,
Restructuring setters here and there,
OnPlatform nested, tidy and bright,
Platform-specific styles get it right!
Styles refined with a bunny's delight ✨

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title appears to have a typo ('esolve' instead of 'Resolve'), but clearly relates to fixing a MAUI XAML source generator error caused by nested markup extensions, which matches the PR objectives.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch development/nuget

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Actionable comments posted: 0

🧹 Nitpick comments (1)

samples/Sample.Maui/Resources/Styles/Style.xaml (1)

957-968: Expanded Setter.Value with OnPlatform cleanly works around the source‑generator bug

Switching from the inline Value="{OnPlatform WinUI={m:GetString Refresh}}" to the Setter.Value + <OnPlatform x:TypeArguments="x:String"> element syntax is correct here and should avoid the MAUIG1001 issue while preserving behavior (only WinUI gets the localized Refresh string; other platforms still get the default value as before).

If you intend to show a text label on non‑WinUI platforms as well, you could optionally add an additional <On Platform="Default" ... />, but that’s outside the scope of this fix.

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 843e4b8 and 2d61d6d.

📒 Files selected for processing (1)

• samples/Sample.Maui/Resources/Styles/Style.xaml (1 hunks)

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• GitHub Check: I-Synergy.Framework PR (Build Build, test and pack assemblies)