Getting started in EJ2 TypeScript ComboBox control

28 Jul 202611 minutes to read

This section explains the steps to create a simple ComboBox and demonstrates the basic usage of the ComboBox component using Essential® JS 2 quickstart seed repository. This seed repository is pre-configured with the Essential® JS 2 package.

This application is integrated with the webpack.config.js configuration and uses the latest version of the webpack-cli. It requires node v14.15.0 or higher. For more information about webpack and its features, refer to the webpack documentation.

Prerequisites

Ensure the following tools are installed on your machine:

Set up the development environment

Clone the Syncfusion® TypeScript (Essential® JS 2) quickstart project from GitHub in the command prompt:

git clone https://github.com/SyncfusionExamples/ej2-quickstart-webpack ej2-quickstart

Navigate to the project folder in the command prompt:

cd ej2-quickstart

Install Syncfusion® ComboBox package

Syncfusion® TypeScript (Essential® JS 2) packages are available on the npmjs.com public registry. You can install all Syncfusion® TypeScript (Essential® JS 2) controls in a single @syncfusion/ej2 package or individual packages for each control.

Use the following command to install the @syncfusion/ej2-dropdowns package:

npm install @syncfusion/ej2-dropdowns --save

Then, install the remaining dependent npm packages using the following command:

npm install

For more information about individual package and alternative installation methods, see the installation guide.

Import Syncfusion® ComboBox CSS styles

Syncfusion® JavaScript controls provide built-in themes, which are available from the npm theme packages. Additionally, themes can be loaded via CDN or customized using the Theme Studio. For more information, refer to the themes documentation.

The quickstart application is preconfigured to use the Fluent2 theme. To install the Fluent2 theme package, use the following command:

npm install @syncfusion/ej2-fluent2-theme --save

The required styles are imported in the ~/src/styles/styles.css file, as shown below:

@import "../../node_modules/@syncfusion/ej2-fluent2-theme/styles/combo-box/index.css";

Learn more about built-in themes and individual control CSS references.

Add Syncfusion® ComboBox control to the application

The ComboBox can be initialized through three different tags which described in Initialize Tags.

Open the application in Visual Studio Code and add the Syncfusion® TypeScript UI controls.

In this article, the ComboBox control is used as an example. Add the following ComboBox element to the ~/src/index.html file.

<!DOCTYPE html>
<html lang="en">

<head>
    <title>Essential JS 2 ComboBox component</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no" />
    <meta name="description" content="Essential JS 2" />
    <meta name="author" content="Syncfusion" />
    <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />
</head>

<body>
    <div id='container' style="margin:0 auto; width:300px;">
        <!--element which is going to render the ComboBox-->
        <input type="text" tabindex="1" id='comboelement' />
    </div>

</body>

</html>

Now, to render the ComboBox control, add the following TypeScript code to the ~/src/app/app.ts file.

import { ComboBox } from '@syncfusion/ej2-dropdowns';

// define the array of data
let sportsData: string[] = ['Badminton', 'Cricket', 'Football', 'Golf', 'Tennis'];

// initialize ComboBox component
let comboBoxObject: ComboBox = new ComboBox({
    //set the data to dataSource property
    dataSource: sportsData
});

// render initialized ComboBox
comboBoxObject.appendTo('#comboelement');

Run the application

Now, run the application in the browser using the following command.

npm run start

The following example illustrates the output in your browser.

import { ComboBox } from '@syncfusion/ej2-dropdowns';

// defined the array of data
let sportsData: string[] = ['Badminton', 'Cricket', 'Football', 'Golf', 'Tennis'];

// initialize ComboBox component
let comboBoxObject: ComboBox = new ComboBox({
    //set the data to dataSource property
    dataSource: sportsData,
    // set placeholder to ComboBox input element
    placeholder: "Select a game"
});

// render initialized ComboBox
comboBoxObject.appendTo('#comboelement');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 ComboBox</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript UI Controls" />
    <meta name="author" content="Syncfusion" />
    <link href="styles.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
</head>

<body>
    <div id='loader'>LOADING....</div>
    <div id='container' style="margin:50px auto 0; width:250px;">
        <br>
        <input type="text" tabindex="1" id='comboelement' />
    </div>
</body>

</html>

Custom values

The ComboBox allows users to enter custom values that are not in the predefined set. By default, this is enabled through the allowCustom property. In this case, both text and value fields are treated as the same. Custom values are sent to the post-back handler when a form is submitted.

import { ComboBox } from '@syncfusion/ej2-dropdowns';

// defined the array of data
let sportsData: { [key: string]: Object }[] = [
    { Id: 'game1', Game: 'Badminton' },
    { Id: 'game2', Game: 'Football' },
    { Id: 'game3', Game: 'Tennis' }
];

// initialize ComboBox component
let comboBoxObject: ComboBox = new ComboBox({
    //set the data to dataSource property
    dataSource: sportsData,
    // By default, its enabled. For your better understanding, showcase this property here.
    allowCustom: true,
    // maps the appropriate column to fields property
    fields: { text: 'Game', value: 'Id' },
    // set placeholder to ComboBox input element
    placeholder: "Select a game"
});

// render initialized ComboBox
comboBoxObject.appendTo('#comboelement');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 ComboBox</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript UI Controls" />
    <meta name="author" content="Syncfusion" />
    <link href="styles.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
</head>

<body>
    <div id='loader'>LOADING....</div>
    <div id='container' style="margin:50px auto 0; width:250px;">
        <br>
        <input type="text" tabindex="1" id='comboelement' />
    </div>
</body>

</html>

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 is 300px.

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

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

import { ComboBox } from '@syncfusion/ej2-dropdowns';

// define the array of data
let sportsData: string[] = ['Badminton', 'Cricket', 'Football', 'Golf', 'Tennis'];

// initialize ComboBox component
let comboBoxObject: ComboBox = new ComboBox({
    //set the data to dataSource property
    dataSource: sportsData,
    //set height to popup list
    popupHeight: '200px',
    //set width to popup list
    popupWidth: '250px',
    // set placeholder to ComboBox input element
    placeholder: "Select a game"
});

// render initialized ComboBox
comboBoxObject.appendTo('#comboelement');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 ComboBox</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript UI Controls" />
    <meta name="author" content="Syncfusion" />
    <link href="styles.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/34.1.29/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
</head>

<body>
    <div id='loader'>LOADING....</div>
    <div id='container' style="margin:50px auto 0; width:250px;">
        <br>
        <input type="text" tabindex="1" id='comboelement' />
    </div>
</body>

</html>

See Also