fix: Allow static x:Bind in DataTemplate without x:DataType

[Copilot]

Summary

Fixed an issue where static x:Bind expressions in DataTemplates failed to compile without an x:DataType specified.

Changes Made

• Explored repository structure and understood x:Bind compilation
• Identified error locations in XamlFileGenerator.cs
• Modified BuildXBindProperties to detect fully static bindings
• Modified event binding code to allow static methods without DataType
• Created comprehensive test cases
• Fixed build errors and formatting issues
• Added unit tests to verify the fix
• Addressed code review feedback with comments
• Fixed CI build error: empty path bindings incorrectly classified as static
• Passed security checks

Technical Details

Property Bindings

• Pre-parse binding to detect if all properties are static (start with "global::")
• Fixed: Empty path bindings (e.g., {x:Bind}) bind to DataContext itself, not static members
• If fully static (has path and all properties start with "global::"), skip DataType requirement
• If not fully static, require x:DataType as before

Event Bindings

• Detect static method paths (contain ':' type qualifier)
• Skip DataType requirement for static methods
• Use page type as placeholder (not used for resolution)

Build Fix

The build error The name '___tctx' does not exist in the current context was caused by:

1. Empty path bindings (e.g., {x:Bind} with just a Converter) were incorrectly classified as "fully static"
2. These bindings were taking the static code path instead of the normal DataTemplate path
3. Fixed by explicitly checking for non-empty path before considering a binding as static

Compatibility

✅ Fully backward compatible
✅ Aligns with WinAppSDK behavior
✅ No breaking changes
✅ Existing bindings unaffected

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Static x:Bind in DataTemplate fails without a DataType</issue_title>
<issue_description>### Current behavior 🐛

If you have a <DataTemplate> without a DataType specified with only static x:Bind in it then it fails to compile with:

error UXAML0001: Unable to find x:DataType in enclosing DataTemplate

Expected behavior 🎯

Should allow you to do x:Bind to static members without needing a DataType. Works in WinAppSdk.

How to reproduce it (as minimally and precisely as possible) 🔬

Put a static x:Bind in a data template with no DataType, for example:

<cwuc:DataGridTemplateColumn>
  <cwuc:DataGridTemplateColumn.CellTemplate>
    <DataTemplate>
      <FontIcon Glyph="{x:Bind d:FontIcons.Role}" />
    </DataTemplate>
  </cwuc:DataGridTemplateColumn.CellTemplate>
</cwuc:DataGridTemplateColumn>

Notice the build fails with the error above.

Workaround 🛠️

No response

Renderer 🎨

• Skia
• Native

Affected platforms 📱💻🖥️

All platforms 🌍 (Except WinAppSdk)

Uno.Sdk version (and other relevant versions) 📦

6.5.0-dev.100

IDE version 🧑‍💻

No response

Anything else we need to know? 💬

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Static x:Bind in DataTemplate fails without a DataType #22216

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[unodevops]

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[MartinZikmund]

@copilot Uno.UI.SourceGenerators.XamlGenerator.XamlCodeGenerator/BindingExpression_With_Converter_07e5b85741c18e42ed743478c0cd3c9b.cs(723,180): error CS0103: The name '___tctx' does not exist in the current context [/agent/_work/1/s/src/Uno.UI.RuntimeTests/Uno.UI.RuntimeTests.Skia.csproj::TargetFramework=net10.0]

[Copilot]

@copilot Uno.UI.SourceGenerators.XamlGenerator.XamlCodeGenerator/BindingExpression_With_Converter_07e5b85741c18e42ed743478c0cd3c9b.cs(723,180): error CS0103: The name '___tctx' does not exist in the c...

Fixed in commit 545ed8f. The issue was that empty path bindings (e.g., {x:Bind Converter={StaticResource ...}}) were incorrectly classified as "fully static" because they have an empty Properties array. These bindings actually bind to the DataContext itself and should use the normal DataTemplate code path with x:DataType. The fix explicitly checks for non-empty paths before considering a binding as static.

[unodevops]

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