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Getting started with Angular ComboBox component

13 May 2021 / 5 minutes to read

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

Dependencies

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

|-- @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.

npm install -g @angular/cli

Create a new application

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.

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

Navigate to the created project folder.

cd syncfusion-angular-combobox

Adding ComboBox package

All the available Essential JS 2 packages are published in npmjs.com registry.

To install ComboBox component, use the following command.

npm install @syncfusion/ej2-angular-dropdowns --save
(or)
npm i @syncfusion/ej2-angular-dropdowns --save

The —save will instruct NPM to include the ComboBox package inside of the dependencies section of the package.json.

Registering ComboBox module

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

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.

@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 ComboBox component. Add the Angular ComboBox by using <ejs-combobox> selector in template section of the app.component.ts file.

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.

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.

ng serve

The following example illustrates the output in your browser.

Source

Preview

app.component.ts

app.module.ts

main.ts

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'];
}

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 { }

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

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' }
    ];
}

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 { }

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

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

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

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'];
}

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 { }

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

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';
}

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 { }

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

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

Getting started with Angular ComboBox component

Dependencies

Setup angular environment

Create a new application

Adding ComboBox package

Registering ComboBox module

Adding CSS reference

Adding ComboBox component

Binding data source

Running the application

Custom values

Configure the popup list

Two-way binding

See Also