Accessibility and UI Automation

TreeDataGrid exposes a full Avalonia automation surface for the grid root, rows, cells, and headers.

Use this layer when you need:

screen-reader friendly selection and focus behavior
reliable UI automation for tests or tooling
custom control derivations that must preserve accessibility contracts

Automation Peer Namespace

The public automation peer types live in Namespace: Avalonia.Controls.Automation.Peers.

Root Control Automation

TreeDataGridAutomationPeer represents the grid itself.

It exposes:

AutomationControlType.DataGrid
selection-provider behavior for row selection
source-aware updates when the bound ITreeDataGridSource changes

Row and Cell Automation

Realized rows and cells expose dedicated peers:

These peers bridge TreeDataGrid concepts to standard automation patterns:

row selection
expand/collapse for hierarchical rows
toggle state for check box cells
value-provider access where a row exposes textual value

Header Automation

Column headers are surfaced separately:

This keeps header navigation and sortable-column discovery visible to automation clients without mixing that behavior into row peers.

Guidance

Prefer the built-in automation peers when using the standard control and templates.
If you subclass TreeDataGrid or replace presenter elements, keep the same automation roles and provider contracts.
Test accessibility-sensitive changes together with selection, expansion, and check box interaction.

API Coverage Checklist