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Customize Group Headers

To customize group headers, specify a groupTemplate. In Angular and Vue, you can declare it in the markup. In React, you can use a rendering function (shown in the code below) or component. If the template is unspecified, group headers display the key data field in bold font.

Angular
HTML
TypeScript
<dx-tag-box
    [dataSource]="tagBoxDataSource"
    [grouped]="true"
    groupTemplate="group"
    displayExpr="name"
    valueExpr="count">
    <div *dxTemplate="let data of 'group'">
        <p>{{data.key}} | Count: {{data.overallCount}}</p>
    </div>
</dx-tag-box>
import { DxTagBoxModule } from "devextreme-angular";
import DataSource from "devextreme/data/data_source";
// ...
export class AppComponent {
    fruitsVegetables = [{
        key: "Fruits",
        items: [
            { name: "Apples", count: 10 },
            { name: "Oranges", count: 12 },
            { name: "Lemons", count: 15 }
        ]
    }, {
        key: "Vegetables",
        items: [
            { name: "Potatoes", count: 5 },
            { name: "Tomatoes", count: 9 },
            { name: "Turnips", count: 8 }
        ]
    }];
    tagBoxDataSource: DataSource = new DataSource({
        store: this.fruitsVegetables,
        map: function(groupedItem) {
            let overallCount = 0;
            groupedItem.items.forEach(function(item) {
                overallCount += item.count;
            })
            return Object.assign(groupedItem, { overallCount: overallCount });
        }
    });
}
@NgModule({
     imports: [
         // ...
         DxTagBoxModule
     ],
     // ...
 })
Vue
<template>
    <DxTagBox
        :data-source="tagBoxDataSource"
        :grouped="true"
        group-template="group"
        display-expr="name"
        value-expr="count">
        <template #group="{data}">
            <p>{{data.key}} | Count: {{data.overallCount}}</p>
        </template>
    </DxTagBox>
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxTagBox } from 'devextreme-vue/tag-box';
import DataSource from "devextreme/data/data_source";

const fruitsVegetables = [{
    key: "Fruits",
    items: [
        { name: "Apples", count: 10 },
        { name: "Oranges", count: 12 },
        { name: "Lemons", count: 15 }
    ]
}, {
    key: "Vegetables",
    items: [
        { name: "Potatoes", count: 5 },
        { name: "Tomatoes", count: 9 },
        { name: "Turnips", count: 8 }
    ]
}];

export default {
    components: {
        DxTagBox
    },
    data() {
        return {
            tagBoxDataSource: new DataSource({
                store: fruitsVegetables,
                map: function(groupedItem) {
                    let overallCount = 0;
                    groupedItem.items.forEach(function(item) {
                        overallCount += item.count;
                    })
                    return Object.assign(groupedItem, { overallCount: overallCount });
                }
            })
        };
    }
}
</script>
React
import React from 'react';
import 'devextreme/dist/css/dx.light.css';

import { TagBox } from 'devextreme-react/tag-box';
import DataSource from "devextreme/data/data_source";

const fruitsVegetables = [{
    key: "Fruits",
    items: [
        { name: "Apples", count: 10 },
        { name: "Oranges", count: 12 },
        { name: "Lemons", count: 15 }
    ]
}, {
    key: "Vegetables",
    items: [
        { name: "Potatoes", count: 5 },
        { name: "Tomatoes", count: 9 },
        { name: "Turnips", count: 8 }
    ]
}];

const renderGroup = (data) => {
    return (
        <p>{data.key} | Count: {data.overallCount}</p>
    );
};

class App extends React.Component {
    constructor(props) {
        super(props);

        this.tagBoxDataSource = new DataSource({
            store: fruitsVegetables,
            map: function(groupedItem) {
                let overallCount = 0;
                groupedItem.items.forEach(function(item) {
                    overallCount += item.count;
                })
                return Object.assign(groupedItem, { overallCount: overallCount });
            }
        });
    }

    render() {
        return (
            <TagBox
                dataSource={this.tagBoxDataSource}
                grouped={true}
                displayExpr="name"
                valueExpr="count"
                groupRender={renderGroup}
            />
        );
    }
}

export default App;

If you use jQuery alone, use DOM manipulation methods to combine the HTML markup for group headers. To apply this markup, use the groupTemplate callback function as shown in the following code.

JavaScript
const fruitsVegetables = [{
    // ...
}];

$(function() {
    $("#tagBoxContainer").dxTagBox({
        dataSource: new DevExpress.data.DataSource({
            store: fruitsVegetables,
            map: function(groupedItem) {
                let overallCount = 0;
                groupedItem.items.forEach(function(item) {
                    overallCount += item.count;
                });
                return $.extend(groupedItem, { overallCount: overallCount })
            }
        }),
        grouped: true,
        groupTemplate: function(groupData, _, groupElement) {
            groupElement.append(
                $("<p>").text(groupData.key + " | Count: " + groupData.overallCount)
            )
        },
        displayExpr: 'name',
        valueExpr: 'count'
    });
});

View Demo

In addition, you can use a 3rd-party template engine to perform the needed customizations. For more information, see the 3rd-Party Template Engines article.

See Also