csharp-expressions.md

title
C# Expressions

C# Expressions

AXSG supports C# expression syntax inside valid XAML forms. This includes simple shorthand expressions, full explicit expressions, interpolation, formatting, ternaries, boolean logic, and source-aware lowering when the expression can be converted into a more efficient binding form.

Supported forms

The expression surface includes:

• shorthand expressions such as {Title} or {HasAccount && AgreedToTerms}
• explicit expression forms where the compiler can clearly identify a C# expression body
• interpolated strings and formatted numeric expressions
• source-qualified forms such as root- or data-context-directed access where supported by the current semantics

Why this matters

These expressions are not handled as plain text macros. AXSG parses and analyzes them against the current XAML scope so it can:

• resolve the correct source object
• validate members and methods at build time
• generate better runtime helpers
• surface language-service completion, hover, references, and definitions

Interactions with compiled bindings

In many cases AXSG can lower a shorthand expression to a compiled binding path or another cheaper generated form. In other cases it keeps the expression as an analyzed C# expression with generated runtime support. The compiler chooses the lowering based on precedence and source resolution rules.

Where to look next

• Guides: C# Expressions
• Inline C# for statement-capable code forms
• Binding and Expression Model
• APIs: xref:XamlToCSharpGenerator.ExpressionSemantics, xref:XamlToCSharpGenerator.Avalonia.Binding