Angular ComboBox Component Overview

The Angular ComboBox component represents a drop-down list that provides editable functionalities, allowing users to choose multiple options from a predefined list. The Ignite UI for Angular ComboBox Component also provides filtering capabilities, grouping and adding custom values to a dropdown list. It can be used as an alternative to the HTML select tag and has several out-of-the-box features such as data binding (local and remote), filtering, grouping, custom templates for items, header, and footer, custom values, and more.

Angular ComboBox Example

In this Angular ComboBox example, you can see how users can filter items and perform selection with the provided data. In addition, the ComboBox exposes keyboard navigation and custom styling capabilities.

Angular ComboBox Features

The combobox control exposes the following features:

Data Binding - local data and remote data
Value Binding
Filtering
Grouping
Custom Values
Templates
Integration with Template Driven Forms and Reactive Forms

Getting Started with Ignite UI for Angular ComboBox

To get started with the Ignite UI for Angular ComboBox component, first you need to install Ignite UI for Angular. In an existing Angular application, type the following command:

ng add igniteui-angular

For a complete introduction to the Ignite UI for Angular, read the getting started topic.

The next step is to import the IgxComboModule in your app.module.ts file.

import { IgxComboModule } from 'igniteui-angular';
// import { IgxComboModule } from '@infragistics/igniteui-angular'; for licensed package

@NgModule({
    imports: [
        ...
        IgxComboModule,
        ...
    ]
})
export class AppModule {}

Alternatively, as of 16.0.0 you can import the IgxComboComponent as a standalone dependency, or use the IGX_COMBO_DIRECTIVES token to import the component and all of its supporting components and directives.

// home.component.ts

import { IGX_COMBO_DIRECTIVES } from 'igniteui-angular';
// import { IGX_COMBO_DIRECTIVES } from '@infragistics/igniteui-angular'; for licensed package

@Component({
    selector: 'app-home',
    template: '<igx-combo></igx-combo>',
    styleUrls: ['home.component.scss'],
    standalone: true,
    imports: [IGX_COMBO_DIRECTIVES]
    /* or imports: [IgxComboComponent] */
})
export class HomeComponent {}

Now that you have the Ignite UI for Angular Combo module or directives imported, you can start using the igx-combo component.

Using the Angular ComboBox Component

After the initial setup, you can bind the igx-combo to data.

@Component({
    selector: 'app-combo-demo',
    template: '<igx-combo [data]="cities"></igx-combo>',
    styleUrls: ['combo-demo.component.scss'],
    standalone: true,
    imports: [IGX_COMBO_DIRECTIVES]
})
export class ComboDemo implements OnInit {
    public cities: { name: string, id: string }[] = [];

    public ngOnInit() {
        this.cities = [{ name: 'London', id: 'UK01' }, { name: 'Sofia', id: 'BG01'}, ...];
    }
}

Our combobox is now bound to the array of cities, but we still haven't told the component which property to use for the items' text and which to use for the value. Let's do that now.

Data value and display properties

Since the combobox is bound to an array of complex data (i.e. objects), we need to specify a property that the control will use to handle the selected items. The control exposes two @Input properties - valueKey and displayKey:

valueKey - Optional, recommended for object arrays - Specifies which property of the data entries will be stored for the combobox's selection. If valueKey is omitted, the combobox value will use references to the data entries (i.e. the selection will be an array of entries from igxCombo.data).
displayKey - Required for object arrays - Specifies which property will be used for the items' text. If no value is specified for displayKey, the combobox will use the specified valueKey (if any).

In our case, we want the combobox to display the name of each city and the combobox value to store the id of each city. Therefore, we are providing these properties to the combobox's displayKey and valueKey, respectively:

<igx-combo [data]="cities" displayKey="name" valueKey="id"></igx-combo>

Note

When the data source is an array of primitives (e.g. string[], number[]), do not specify a valueKey and displayKey. Primitive values will be used for both value and text.

Two-Way Binding

The combobox component fully supports two-way data-binding with [(ngModel)] as well as usage in template driven and reactive forms. The combobox selection can be accessed either through two-way binding or through the selection API. We can pass an array of items of the same type as the ones in the combobox's selection (based on valueKey) and any time one changes, the other is updated accordingly.

In the following example, the cities Sofia and London will initially be selected. Any further changes in the combobox's selection will reflect on the selectedCities array.

<igx-combo [data]="cities" [(ngModel)]="selectedCities" displayKey="name" valueKey="id"></igx-combo>

export class MyCombo {
    public cities: { name: string, id: string }[] = [
                   { name: 'Sofia', id: 'BG01' }, { name: 'London', id: 'UK01' }, ...];
    public selectedCities: string[] = ['BG01', 'UK01'];
}

Two-way binding can also be achieved without a specified valueKey. For example, if valueKey is omitted, the bound model will look like this:

export class MyCombo {
    public cities: { name: string, id: string } [] = [
                   { name: 'Sofia', id: 'BG01' }, { name: 'London', id: 'UK01' }, ...];
    public selectedCities: { name: string, id: string } [] = [this.cities[0], this.cities[1]];
}

Selection API

The combobox component exposes API that allows getting and manipulating the current selection state of the control.

One way to get the combobox's selection is via the selection property. It returns an array of values which correspond to the selected items, depending on the specified valueKey (if any).

In our example, selection will return an array of the selected cities' ids:

export class MyCombo {
    ...
    public selection: string[] = this.combo.selection;
}

Using the selection API, you can also change the combobox's selected items without user interaction with the control - via a button click, as a response to an Observable changing, etc. For example, we can implement a button that selects a set of cities, using the select() method:

<igx-combo [data]="cities" displayKey="name" valueKey="id"></igx-combo>
<button igxButton (click)="selectFavorites()">Select Favorites</button>

When clicking the button, the cities London and Sofia will be added to the combobox's selection:

export class MyExampleCombo {
    @ViewChild(IgxComboComponent, { read: IgxComboComponent, static: true })
    public combo: IgxComboComponent;
    ...
    selectFavorites(): void {
        this.combo.select(['UK01', 'BG01']);
    }
}

The combobox also fires an event every time its selection changes - selectionChanging(). The emitted event arguments, IComboSelectionChangingEventArgs, contain information about the selection prior to the change, the current selection and the items that were added or removed. The event can also be cancelled, preventing the selection update with the new array of items.

Binding to the event can be done through the proper @Output property on the igx-combo tag:

<igx-combo [data]="cities" displayKey="name" valueKey="id"
           (selectionChanging)="handleCityChange($event)">
</igx-combo>

In the following example, when a city is added or removed from the selection, a handler that updates the statistic visualization is fired:

export class MyExampleCombo {
    ...
    handleCityChange(event: IComboSelectionChangeEventArgs): void {
        for (const item of event.added) {
            this.addToVisualization(item);
        }
        for (const item of event.removed) {
            this.removeFromVisualization(item);
        }
    }
}

Single Selection

By default, the combo control provides multiple selection. The snippet below demonstrates how to achieve single selection in the component by attaching a handler to the selectionChanging event:

<igx-combo [data]="lData" (selectionChanging)="singleSelection($event)"></igx-combo>

public singleSelection(event: IComboSelectionChangeEventArgs) {
    if (event.added.length) {
        event.newValue = event.added;
    }
}

Note: It is recommended to use the igxSimpleCombo instead of modifying the igxCombo like it is shown above.

When combobox is closed and focused:

ArrowDown or Alt + ArrowDown will open the combobox's drop down and will move focus to the search input.

When combobox is opened and search input is focused:

ArrowUp or Alt + ArrowUp will close the combobox's drop down and will move focus to the closed combobox.
ArrowDown will move focus from the search input to the first list item. If the list is empty and custom values are enabled will move it to the Add new item button.

Note

Any other key stroke will be handled by the input.

When combobox is opened and list item is focused:

ArrowDown will move to the next list item. If the active item is the last one in the list and custom values are enabled, the focus will be moved to the Add item button.
ArrowUp will move to the previous list item. If the active item is the first one in the list, the focus will be moved back to the search input.
End will move to the last list item.
Home will move to the first list item.
Space will select/deselect the active list item.
Enter will confirm the already selected items and will close the list.
Esc will close the list.

When combobox is opened, allow custom values are enabled and add item button is focused:

Enter will add a new item with valueKey and displayKey equal to the text in the search input and will select the new item.
ArrowUp focus will be moved back to the last list item or if the list is empty, will be moved to the search input.

Angular ComboBox Styling

Using the Ignite UI for Angular Theming, we can greatly alter the combobox appearance. First, in order for us to use the functions exposed by the theme engine, we need to import the index file in our style file:

@use "igniteui-angular/theming" as *;

// IMPORTANT: Prior to Ignite UI for Angular version 13 use:
// @import '~igniteui-angular/lib/core/styles/themes/index';

Following the simplest approach, we create a new theme that extends the combo-theme and accepts the $search-separator-border-color parameter:

$custom-combo-theme: combo-theme(
    $search-separator-border-color: #1a5214
);

The IgxComboComponent uses the IgxDropDownComponent internally as an item container. It also includes the IgxInputGroup and the IgxCheckbox components. Creating new themes, that extend these components' themes, and scoping them under the respective classes will let you change the combobox styles:

$custom-drop-down-theme: drop-down-theme(
    $background-color: #d9f5d6,
    $header-text-color: #1a5214,
    $item-text-color: #1a5214,

    $focused-item-background: #72da67,
    $focused-item-text-color: #1a5214,
    $hover-item-background: #a0e698,
    $hover-item-text-color: #1a5214,

    $selected-item-background: #a0e698,
    $selected-item-text-color: #1a5214,
    $selected-hover-item-background: #72da67,
    $selected-hover-item-text-color: #1a5214,
    $selected-focus-item-background: #72da67,
    $selected-focus-item-text-color: #1a5214,
);

$custom-checkbox-theme: checkbox-theme(
    $border-radius: 10px,
    $fill-color: #1a5214,
    $empty-color: #1a5214,
);

The last step is to include the component's theme.

:host {
    @include css-vars($custom-combo-theme);
    @include css-vars($custom-drop-down-theme);
    @include css-vars($custom-checkbox-theme);
}

Note

The IgxCombo component uses the IgxOverlay service to hold and display the combobox items list container. To properly scope your styles you might have to use an OverlaySetting.outlet. For more details check the IgxOverlay Styling Guide.

Note

The default type of the IgxCombo is box unlike the IgxSelect where it is line.

Demo

Known Issues

The combobox input that displays the selected items is not editable. However, due to browser specifics in FireFox, the cursor is visible.
The combobox does not have input for sizing its height. In the future, the IgxInputGroup component will expose an option that allows custom sizing, and then the IgxCombo will use the same functionality for proper styling and better consistency.
When the combobox is bound to an array of primitive data which contains undefined (i.e. [ undefined, ...]), undefined is not displayed in the dropdown. When it is bound to an array of complex data (i.e. objects) and the value used for valueKey is undefined, the item will be displayed in the dropdown, but cannot be selected.
When the combobox is bound to a remote service and there is a predefined selection, its input will remain blank until the requested data is loaded.

Note

The combobox uses igxForOf directive internally hence all igxForOf limitations are valid for the combobox. For more details see igxForOf Known Issues section.

API Summary

Additional angular components and/or directives with relative APIs that were used:

Theming Dependencies

Additional Resources

Our community is active and always welcoming to new ideas.

Angular ComboBox Component Overview

Angular ComboBox Example

Angular ComboBox Features

Getting Started with Ignite UI for Angular ComboBox

Using the Angular ComboBox Component

Data value and display properties

Note

Two-Way Binding

Selection API

Single Selection

Keyboard Navigation

Note

Angular ComboBox Styling

Note

Note

Demo

Known Issues

Note

API Summary

Theming Dependencies

Additional Resources

Theming