Avalonia/docs/debug-xaml-compiler.md

Debugging the XAML Compiler

The Avalonia XAML compiler can be debugged by setting an MSBuild property which triggers a debugger launch during compilation. This allows you to step through the XAML compilation process and troubleshoot issues.

To enable XAML compiler debugging, set the AvaloniaXamlIlDebuggerLaunch MSBuild property to true in your project file:

<PropertyGroup>
  <AvaloniaXamlIlDebuggerLaunch>true</AvaloniaXamlIlDebuggerLaunch>
</PropertyGroup>

When this property is enabled, the XAML compiler will call Debugger.Launch() on startup, which prompts you to attach a debugger to the compiler process.

If you're working with the Sandbox project in the Avalonia repository, you can enable debugging by simply uncommenting the property line in the project file.