Property Elements, TemplateBinding, and Attached Properties

AXSG treats property-element syntax as a first-class surface in both the compiler and the language service.

Owner-qualified property elements

Property elements such as <Window.IsVisible> or <Grid.RowDefinitions> are resolved as two linked semantic targets:

the owner type (Window, Grid)
the property (IsVisible, RowDefinitions)

That matters for:

completion after .
hover and definition on either side of the qualified name
references and rename for the owner type or the property

Attached properties

Attached property usage participates in the same owner-qualified resolution model.

<Border Grid.Row="1" />
<Grid.RowDefinitions>
  <RowDefinition Height="Auto" />
</Grid.RowDefinitions>

Both attribute and property-element forms map back to the same underlying symbol. This is why references and rename can flow between the attached-property attribute form and the owner-qualified property-element form.

`TemplateBinding`

TemplateBinding is treated as a property reference against the templated control type rather than as opaque text.

<Border BorderBrush="{TemplateBinding BorderBrush}" />

Navigation and references on BorderBrush resolve to the actual Avalonia property declaration, including inside control themes and templates.

Why this matters for tooling

These surfaces are easy to get wrong if the editor only tokenizes XML text. AXSG resolves them semantically, so it can distinguish:

owner token vs property token
attached property usage vs ordinary attribute text
template-bound property reference vs plain string content

Common workflows

use completion after <Window. or <Grid. to insert the correct property element name without duplicating the owner token
use references on an attached property to gather both attribute and property-element usages
use definition on TemplateBinding property names to inspect the real Avalonia property being referenced