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Getting started with Angular ComboBox component

08 Dec 2022 / 6 minutes to read

This section explains how to create a simple ComboBox component and configure its available functionalities in Angular.

To get started quickly with angular ComboBox component using angular CLI, you can check the video below.

Dependencies

The following list of dependencies are required to use the Angular ComboBox component in your application.

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|-- @syncfusion/ej2-angular-dropdowns
    |-- @syncfusion/ej2-base
    |-- @syncfusion/ej2-data
    |-- @syncfusion/ej2-angular-base
    |-- @syncfusion/ej2-dropdowns
        |-- @syncfusion/ej2-lists
        |-- @syncfusion/ej2-inputs
        |-- @syncfusion/ej2-navigations
        |-- @syncfusion/ej2-popups
            |-- @syncfusion/ej2-buttons

Setup angular environment

Angular provides the easiest way to set angular CLI projects using Angular CLI tool.

Install the CLI application globally to your machine.

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npm install -g @angular/cli

Create a new application

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ng new syncfusion-angular-combobox

By default, it install the CSS style base application. To setup with SCSS, pass —style=scss argument on create project.

Example code snippet.

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ng new syncfusion-angular-combobox --style=scss

Navigate to the created project folder.

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cd syncfusion-angular-combobox

Installing Syncfusion ComboBox package

Syncfusion packages are distributed in npm as @syncfusion scoped packages. You can get all the Angular Syncfusion package from npm link.

Currently, Syncfusion provides two types of package structures for Angular components,

  1. Ivy library distribution package format
  2. Angular compatibility compiler(Angular’s legacy compilation and rendering pipeline) package.

Ivy library distribution package

Syncfusion Angular packages(>=20.2.36) has been moved to the Ivy distribution to support the Angular Ivy rendering engine and the package are compatible with Angular version 12 and above. To download the package use the below command.

Add @syncfusion/ej2-angular-dropdowns package to the application.

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npm install @syncfusion/ej2-angular-dropdowns --save

Angular compatibility compiled package(ngcc)

For Angular version below 12, you can use the legacy (ngcc) package of the Syncfusion Angular components. To download the ngcc package use the below.

Add @syncfusion/ej2-angular-dropdowns@ngcc package to the application.

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npm install @syncfusion/ej2-angular-dropdowns@ngcc --save

To mention the ngcc package in the package.json file, add the suffix -ngcc with the package version as below.

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@syncfusion/ej2-angular-dropdowns:"20.2.38-ngcc"

Note: If the ngcc tag is not specified while installing the package, the Ivy Library Package will be installed and this package will throw a warning.

Registering ComboBox module

Import ComboBox module into Angular application(app.module.ts) from the package @syncfusion/ej2-angular-dropdowns.

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import { NgModule }      from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
// import the ComboBoxModule for the ComboBox component
import { ComboBoxModule } from '@syncfusion/ej2-angular-dropdowns';
import { AppComponent }  from './app.component';

@NgModule({
  //declaration of ej2-angular-dropdowns module into NgModule
  imports:      [ BrowserModule, ComboBoxModule ],
  declarations: [ AppComponent ],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

Adding CSS reference

The following CSS files are available in ../node_modules/@syncfusion package folder. This can be referenced in [src/styles.css] using following code.

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@import '../node_modules/@syncfusion/ej2-base/styles/material.css';
@import '../node_modules/@syncfusion/ej2-buttons/styles/material.css';
@import '../node_modules/@syncfusion/ej2-dropdowns/styles/material.css';
@import '../node_modules/@syncfusion/ej2-inputs/styles/material.css';
@import '../node_modules/@syncfusion/ej2-popups/styles/material.css';
@import '../node_modules/@syncfusion/ej2-lists/styles/material.css';
@import '../node_modules/@syncfusion/ej2-angular-dropdowns/styles/material.css';

Adding ComboBox component

Modify the template in [src/app/app.component.ts] file to render the Angular ComboBox component. Add the Angular ComboBox by using <ejs-combobox> selector in template section of the app.component.ts file.

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import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  // specifies the template string for the ComboBox component
  template: `<ejs-combobox id='comboelement'></ejs-combobox>`
})
export class AppComponent  { }

Binding data source

After initializing, populate the ComboBox with data using the dataSource property. Here, an array of string values passed to ComboBox component.

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import { Component } from '@angular/core';

@Component({
selector: 'app-root',
// specifies the template string for the ComboBox component
template: `<ejs-combobox id='comboelement' [dataSource]='data'></ejs-combobox>`
})
export class AppComponent {
constructor() {
}
// defined the array of data
public data: string[] = ['Cricket', 'Football', 'Rugby', 'Snooker', 'Tennis'];
}

Running the application

After completing the configuration required to render a basic ComboBox, run the following command to display the output in your default browser.

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ng serve

The following example illustrates the output in your browser.

Source
Preview
app.component.ts
app.module.ts
main.ts
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import { Component } from '@angular/core';

@Component({
selector: 'app-root',
// specifies the template string for the ComboBox component with dataSource
template: `<ejs-combobox id='comboelement' [dataSource]='data' placeholder = 'Select a game'></ejs-combobox>`
})
export class AppComponent {
constructor() {
}
// defined the array of data
public data: string[] = ['Cricket', 'Football', 'Rugby', 'Snooker', 'Tennis'];
}
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import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { ComboBoxModule } from '@syncfusion/ej2-angular-dropdowns';
import { ButtonModule } from '@syncfusion/ej2-angular-buttons';
/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,FormsModule, ReactiveFormsModule, ComboBoxModule,ButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent]
})
export class AppModule { }
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import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);

Custom values

The ComboBox allows the user to give input as custom value which is not required to present in predefined set of values. By default, this support is enabled by allowCustom property. In this case, both text field and value field considered as same. The custom value will be sent to post back handler when a form is about to be submitted.

Source
Preview
app.component.ts
app.module.ts
main.ts
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import { Component } from '@angular/core';

@Component({
selector: 'app-root',
// specifies the template string for the ComboBox component with dataSource
template: `<ejs-combobox id='comboelement' [dataSource]='sportsData' [fields]=fields allowCustom=true placeholder = 'Select a game'></ejs-combobox>`
})
export class AppComponent {
constructor() {
}
public fields: Object = {text: 'Game', value: 'Id'};
// defined the array of data
public sportsData: { [key: string]: Object }[] = [
    { Id: 'game1', Game: 'Badminton' },
    { Id: 'game2', Game: 'Football' },
    { Id: 'game3', Game: 'Tennis' }
];
}
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import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { ComboBoxModule } from '@syncfusion/ej2-angular-dropdowns';
import { ButtonModule } from '@syncfusion/ej2-angular-buttons';
/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,FormsModule, ReactiveFormsModule, ComboBoxModule,ButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent]
})
export class AppModule { }
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import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);

Configure the popup list

By default, the width of the popup list automatically adjusts according to the ComboBox input element’s width, and the height of the popup list has ‘300px’.

The height and width of the popup list can also be customized using the popupHeight  and popupWidth property respectively.

In the following sample, popup list’s width and height are configured.

Source
Preview
app.component.ts
app.module.ts
main.ts
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import { Component } from '@angular/core';

@Component({
selector: 'app-root',
// specifies the template string for the ComboBox component with value property
template: `<ejs-combobox id='comboelement' #samples [dataSource]='data' placeholder='Select a game' popupHeight='200px' popupWidth='250px'></ejs-combobox>`
})
export class AppComponent {
constructor() {
}
// define the array of data
public data: string[] = ['Cricket', 'Football', 'Golf', 'Rugby', 'Snooker', 'Tennis'];
}
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import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { ComboBoxModule } from '@syncfusion/ej2-angular-dropdowns';
import { ButtonModule } from '@syncfusion/ej2-angular-buttons';
/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,FormsModule, ReactiveFormsModule, ComboBoxModule,ButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent]
})
export class AppModule { }
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import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);

Two-way binding

In ComboBox, the value property supports two-way binding functionality. The following example demonstrates how to work the two-way binding functionality in ComboBox.

Source
Preview
app.component.ts
app.module.ts
main.ts
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import { Component } from '@angular/core';

@Component({
selector: 'app-root',
// specifies the template string for the ComboBox component and
// input element for checking the two-way binding support using value property
template: `
<ejs-combobox id='comboelement' [dataSource]='data' [(value)]='value' placeholder="Select a game"></ejs-combobox>
<div style='margin-top: 50px'>
    <input type="text" [(ngModel)]="value" style='width:245px;height:25px' />
 </div>
`
})
export class AppComponent {
constructor() {
}
// defined the array of complex data
public data: string[] = [ 'Badminton', 'Football', 'Rugby', 'Snooker', 'Tennis' ];
// set a value to pre-select
public value: string = 'Badminton';
}
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import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { ComboBoxModule } from '@syncfusion/ej2-angular-dropdowns';
import { ButtonModule } from '@syncfusion/ej2-angular-buttons';
/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,FormsModule, ReactiveFormsModule, ComboBoxModule,ButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent]
})
export class AppModule { }
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import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);

You can refer to our Angular ComboBox feature tour page for its groundbreaking feature representations. You can also explore our Angular ComboBox example that shows how to render the ComboBox in Angular.

See Also