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. |
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 |
- 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.
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