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Sorting and grouping in JavaScript ListBox control

Sorting

The ListBox supports sorting of available items in the alphabetical order that can be either ascending or descending. This can achieved using sortOrder property. Sort order can be None, Ascending or Descending.

In the following example, the SortOrder is set as Descending.

Source
Preview
app.ts
index.html
import { ListBox } from '@syncfusion/ej2-dropdowns';

let countryData: { [key: string]: Object }[] = [
    { "Name": "Australia", "Code": "AU" },
    { "Name": "Bermuda", "Code": "BM" },
    { "Name": "Canada", "Code": "CA" },
    { "Name": "Cameroon", "Code": "CM" },
    { "Name": "Denmark", "Code": "DK" },
    { "Name": "France", "Code": "FR" },
    { "Name": "Finland", "Code": "FI" },
    { "Name": "Germany", "Code": "DE" },
    { "Name": "Hong Kong", "Code": "HK" }
];

//initiates the component
let listObj: ListBox = new ListBox({
    dataSource: countryData,
    fields: { text: 'Name' },
    sortOrder: 'Descending'
});


listObj.appendTo('#listbox');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>Essential JS 2 ListBox</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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/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:0 auto; width:250px;">
        <input id='listbox' />
    </div>
</body>

</html>

Grouping

The ListBox supports to wrap the nested element into a group based on its category. The category of each list item can be mapped with groupBy field in the data table.

In the following example, vegetables are grouped based on its category.

Source
Preview
app.ts
index.html
import { ListBox } from '@syncfusion/ej2-dropdowns';

let vegetableData: { [key: string]: Object }[] = [
    { "Vegetable": "Cabbage", "Category": "Leafy and Salad", "Id": "item1" },
    { "Vegetable": "Spinach", "Category": "Leafy and Salad", "Id": "item2" },
    { "Vegetable": "Wheat grass", "Category": "Leafy and Salad", "Id": "item3" },
    { "Vegetable": "Yarrow", "Category": "Leafy and Salad", "Id": "item4" },
    { "Vegetable": "Pumpkins", "Category": "Leafy and Salad", "Id": "item5" },
    { "Vegetable": "Chickpea", "Category": "Beans", "Id": "item6" },
    { "Vegetable": "Green bean", "Category": "Beans", "Id": "item7" },
    { "Vegetable": "Horse gram", "Category": "Beans", "Id": "item8" },
    { "Vegetable": "Garlic", "Category": "Bulb and Stem", "Id": "item9" },
    { "Vegetable": "Nopal", "Category": "Bulb and Stem", "Id": "item10" },
    { "Vegetable": "Onion", "Category": "Bulb and Stem", "Id": "item11" }
];

//initiates the component
let listObj: ListBox = new ListBox({
    dataSource: vegetableData,

    // Map the appropriate columns to fields property along with groupBy option.
    fields: { groupBy: 'Category', text: 'Vegetable', value: 'Id' }
});


listObj.appendTo('#listbox');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>Essential JS 2 ListBox</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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/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:0 auto; width:250px;">
        <input id='listbox' />
    </div>
</body>

</html>

HTML element

The ListBox also supports grouping of list items under specific groups by initiating the <select> element using optgroup. The nested items are wrapped based on the <optgroup> tag that is presents in the <select> element.

Source
Preview
app.ts
index.html
import { ListBox } from '@syncfusion/ej2-dropdowns';

//initiates the component
let listObj: ListBox = new ListBox({});


listObj.appendTo('#listbox');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>Essential JS 2 ListBox</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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/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:0 auto; width:250px;">
        <select id="listbox">
            <optgroup label="Beans">
                <option value="1">Chickpea</option>
                <option value="2">Green bean</option>
                <option value="3">Horse gram</option>
            </optgroup>
            <optgroup label="Leafy and Salad">
                <option value="4">Cabbage</option>
                <option value="5">Spinach</option>
                <option value="6">Wheat grass</option>
            </optgroup>
        </select>
    </div>
</body>

</html>

See Also