Multiselect - Angular

<docs-decorative-header title="Multiselect"> </docs-decorative-header>

Overview

The multiselect pattern combines a read-only combobox trigger with a multi-select listbox popup to create highly accessible multiple-selection dropdowns with keyboard navigation and screen reader support.

<docs-tab-group> <docs-tab label="Basic"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/icons/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/icons/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/icons/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/icons/app/app.css"/> </docs-code-multifile> </docs-tab> <docs-tab label="Material"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/icons/material/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/icons/material/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/icons/material/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/icons/material/app/app.css"/> </docs-code-multifile> </docs-tab> <docs-tab label="Retro"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/icons/retro/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/icons/retro/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/icons/retro/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/icons/retro/app/app.css"/> </docs-code-multifile> </docs-tab> </docs-tab-group>

Usage

The multiselect pattern works best when users need to choose multiple related items from a familiar set of options.

Consider using this pattern when:

Users need multiple selections - Tags, categories, filters, or labels where multiple choices apply
The option list is fixed (fewer than 20 items) - Users can scan options without search
Filtering content - Multiple criteria can be active simultaneously
Assigning attributes - Labels, permissions, or features where multiple values make sense
Related choices - Options that logically work together (such as selecting multiple team members)

Avoid this pattern when:

Only single selection is needed - Use the Select pattern for simpler single-choice dropdowns
The list has more than 20 items with search needed - Use the Autocomplete pattern with multiselect capability
Most or all options will be selected - A checklist pattern provides better visibility
Choices are independent binary options - Individual checkboxes communicate the choices more clearly

Features

The multiselect pattern combines Combobox and Listbox directives to provide a fully accessible dropdown with:

Keyboard Navigation - Navigate options with arrow keys, toggle with Space, close with Escape
Screen Reader Support - Built-in ARIA attributes including aria-multiselectable
Selection Count Display - Shows compact "Item + 2 more" pattern for multiple selections
Signal-Based Reactivity - Reactive state management using Angular signals
Smart Positioning - CDK Overlay handles viewport edges and scrolling
Persistent Selection - Selected options remain visible with checkmarks after selection

Examples

Basic multiselect

Users need to select multiple items from a list of options. A readonly combobox paired with a multi-enabled listbox provides familiar multiselect functionality with full accessibility support.

<docs-tab-group> <docs-tab label="Basic"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/basic/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/basic/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/basic/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/basic/app/app.css"/> </docs-code-multifile> </docs-tab> <docs-tab label="Material"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/basic/material/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/basic/material/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/basic/material/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/basic/material/app/app.css"/> </docs-code-multifile> </docs-tab> <docs-tab label="Retro"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/basic/retro/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/basic/retro/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/basic/retro/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/basic/retro/app/app.css"/> </docs-code-multifile> </docs-tab> </docs-tab-group>

The multi attribute on ngListbox enables multiple selection. Press Space to toggle options, and the popup remains open for additional selections. The display shows the first selected item plus a count of remaining selections.

Multiselect with custom display

Options often need visual indicators like icons or colors to help users identify choices. Custom templates within options allow rich formatting while the display value shows a compact summary.

Each option displays an icon alongside its label. The display value updates to show the first selection's icon and text, followed by a count of additional selections. Selected options show a checkmark for clear visual feedback.

Controlled selection

Forms sometimes need to limit the number of selections or validate user choices. Programmatic control over selection enables these constraints while maintaining accessibility.

<docs-tab-group> <docs-tab label="Basic"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/limited/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/limited/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/limited/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/limited/app/app.css"/> </docs-code-multifile> </docs-tab> <docs-tab label="Material"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/limited/material/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/limited/material/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/limited/material/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/limited/material/app/app.css"/> </docs-code-multifile> </docs-tab> <docs-tab label="Retro"> <docs-code-multifile preview hideCode path="adev/src/content/examples/aria/multiselect/src/limited/retro/app/app.ts"> <docs-code header="app.ts" path="adev/src/content/examples/aria/multiselect/src/limited/retro/app/app.ts"/> <docs-code header="app.html" path="adev/src/content/examples/aria/multiselect/src/limited/retro/app/app.html"/> <docs-code header="app.css" path="adev/src/content/examples/aria/multiselect/src/limited/retro/app/app.css"/> </docs-code-multifile> </docs-tab> </docs-tab-group>

This example limits selections to two items. When the limit is reached, unselected options are disabled to prevent further selections, and the combobox display updates to reflect the choices.

Testing

The multiselect pattern can be tested using a combination of ComboboxHarness and ListboxHarness from @angular/aria/combobox/testing and @angular/aria/listbox/testing. Here is an example of how to use the harnesses to test a multiselect component:

typescript

import {ComponentFixture, TestBed} from '@angular/core/testing';
import {HarnessLoader} from '@angular/cdk/testing';
import {TestbedHarnessEnvironment} from '@angular/cdk/testing/testbed';
import {ComboboxHarness} from '@angular/aria/combobox/testing';
import {ListboxHarness} from '@angular/aria/listbox/testing';
import {MyMultiselectComponent} from './my-multiselect'; // Your component

describe('MyMultiselectComponent', () => {
  let fixture: ComponentFixture<MyMultiselectComponent>;
  let loader: HarnessLoader;

  beforeEach(async () => {
    TestBed.configureTestingModule({
      imports: [MyMultiselectComponent],
    });

    fixture = TestBed.createComponent(MyMultiselectComponent);
    await fixture.whenStable();
    loader = TestbedHarnessEnvironment.loader(fixture);
  });

  it('should allow selecting multiple options', async () => {
    const select = await loader.getHarness(ComboboxHarness);

    // Open the dropdown
    await select.open();

    // Get the listbox harness from the popup
    const listbox = await select.getPopupWidget(ListboxHarness);
    expect(await listbox.isMulti()).toBe(true);

    const options = await listbox.getOptions();

    // Select first and second options
    await options[0].click();
    await options[1].click();

    // Verify both options are selected
    expect(await options[0].isSelected()).toBe(true);
    expect(await options[1].isSelected()).toBe(true);

    // Close the dropdown
    await select.close();

    // Verify value is updated (e.g., comma separated list or count)
    expect(await (await select.host()).text()).toContain('Option 1, Option 2');
  });
});

APIs

The multiselect pattern uses the following directives from Angular's Aria library. See the full API documentation in the linked guides.

Combobox directives

The multiselect pattern uses ngCombobox directly on the trigger element (such as a div or button) to create a select-like multiselect dropdown.

Inputs

Property	Type	Default	Description
`disabled`	`boolean`	`false`	Disables the entire multiselect

See the Combobox API documentation for complete details on all available inputs and signals.

Popup directives

The structural ngComboboxPopup directive marks the overlay template and requires a reference to the parent combobox:

Property	Type	Description
`combobox`	`Combobox`	Required reference to the parent `Combobox`

ComboboxWidget directive

The ngComboboxWidget directive bridges the listbox with the combobox trigger to support active-descendant focus tracking.

Property	Type	Description
`activeDescendant`	`string \| undefined`	The ID of the currently active option (bound to `listbox.activeDescendant()`) to update the `aria-activedescendant` attribute on the trigger

Listbox directives

The multiselect pattern uses ngListbox with the multi attribute for multiple selection and ngOption for each selectable item.

Inputs

Property	Type	Default	Description
`multi`	`boolean`	`false`	Set to `true` to enable multiple selection
`selectionMode`	`'follow'` \| `'explicit'`	`'follow'`	Set to `'explicit'` so options are toggled explicitly via click/Space instead of following active focus
`focusMode`	`'roving'` \| `'activedescendant'`	`'roving'`	The focus strategy used by the listbox. Set to `'activedescendant'` so browser focus remains on the combobox trigger.
`tabIndex`	`number`	`0`	The tabindex of the listbox. Set to `-1` to prevent keyboard focus from entering the popup container in active-descendant mode.

Model

Property	Type	Description
`value`	`ModelSignal<any[]>`	Two-way bindable array of selected values

When multi is true, users can select multiple options using Space to toggle selection. The popup remains open after selection, allowing additional choices.

See the Listbox API documentation for complete details on listbox configuration, selection modes, and option properties.

Positioning

The multiselect pattern integrates with CDK Overlay for smart positioning. Use cdkConnectedOverlay to handle viewport edges and scrolling automatically.