Angular TreeView - Accessibility

Accessibility Features Overview

NOTE
The overall accessibility level of your application depends on the TreeView features that you use.
Accessibility Requirement Support Level
Right-to-Left Support
Keyboard Navigation Support
Screen Reader Support
Contrast Color Theme
Mobile Device Support
Lighthouse Accessibility Validation
Axe Accessibility Validation
WAVE Accessibility Validation
Section 508 Support
WCAG 2.x Support
  • - All component features meet the requirement
  • - Some component features may not meet the requirement
  • - Accessibility requirement is not supported

Accessibility Standards Compliance

The TreeView component meets a variety of Section 508 and WCAG 2.x compliance standards. Known exceptions:

Section 508 criteria WCAG 2.x criteria Exception description
501 (Web)(Software)
504.2 (Authoring Tool)
602.3 (Support Docs)		 1.4.3 Contrast (Minimum) (Level AA)
1.4.11 Non-text Contrast (Level AA 2.1 and 2.2)		 TreeView does not support Windows High Contrast themes.

The component also complies with the European Accessibility Act (EAA) and Americans with Disabilities Act (ADA) directives.

Keyboard Navigation

A user can use the following keys to interact with the TreeView component:

Key Action
Shift + Mouse Wheel Scrolls the content left/right if the scrollDirection property is "horizontal" or "both".
↑ / ↓ Moves focus to the previous/next node.
Home / End Moves focus to the first/last node.
→ Expands the node.
← Collapses the node.
Asterisk Sign (*) Expands all nodes. Available only if expandAllEnabled is set to true.
Minus Sign (-) Collapses all nodes. Available only if expandAllEnabled is set to true.
Enter or Space Selects the node.
Shift + ↑ / Shift + ↓ Extends selection up/down by one node.1
Shift + Home Extends selection up to the first node.1
Shift + End Extends selection down to the last node.1
  1. If showCheckBoxesMode is set to "none", this action has no effect.

Use the registerKeyHandler(key, handler) method to implement a custom handler for a key.

jQuery
JavaScript
function registerKeyHandlers () {
    const treeView = $("#treeViewContainer").dxTreeView("instance");
    treeView.registerKeyHandler("backspace", function(e) {
        // The argument "e" contains information on the event
    });
    treeView.registerKeyHandler("space", function(e) {
        // ...
    });
}
Angular
TypeScript
import { ..., ViewChild, AfterViewInit } from '@angular/core';
import { DxTreeViewModule, DxTreeViewComponent } from 'devextreme-angular';
// ...
export class AppComponent implements AfterViewInit {
    @ViewChild(DxTreeViewComponent, { static: false }) treeView: DxTreeViewComponent;
    // Prior to Angular 8
    // @ViewChild(DxTreeViewComponent) treeView: DxTreeViewComponent;

    ngAfterViewInit () {
        this.treeView.instance.registerKeyHandler('backspace', function(e) {
            // The argument "e" contains information on the event
        });
        this.treeView.instance.registerKeyHandler('space', function(e) {
            // ...
        });
    }
}
@NgModule({
    imports: [
        // ...
        DxTreeViewModule
    ],
    // ...
})
Vue
<template>
    <DxTreeView :ref="myTreeViewRef" />
</template>
<script>
import 'devextreme/dist/css/dx.light.css';

import DxTreeView from 'devextreme-vue/tree-view';

const myTreeViewRef = 'my-tree-view';

export default {
    components: {
        DxTreeView
    },
    data() {
        return {
            myTreeViewRef
        }
    },
    computed: {
        treeView: function() {
            return this.$refs[myTreeViewRef].instance;
        }
    },
    mounted: function() {
        this.treeView.registerKeyHandler('backspace', function(e) {
            // The argument "e" contains information on the event
        });
        this.treeView.registerKeyHandler('space', function(e) {
            // ...
        });
    }
}
</script>
React
App.js
import React from 'react';
import 'devextreme/dist/css/dx.light.css';

import { TreeView } from 'devextreme-react/tree-view';

class App extends React.Component {
    constructor(props) {
        super(props);

        this.treeViewRef = React.createRef();
    }

    render() {
        return (
            <TreeView ref={this.treeViewRef} />
        );
    }

    get treeView() {
        return this.treeViewRef.current.instance();
    }

    componentDidMount() {
        this.treeView.registerKeyHandler('backspace', function(e) {
            // The argument "e" contains information on the event
        });
        this.treeView.registerKeyHandler('space', function(e) {
            // ...
        });
    }
}

export default App;

Screen Reader Support

The TreeView component supports screen readers and complies to WAI-ARIA standards.