jQuery SelectBox - Customize Group Headers
By default, group headers display text of the key field in a bold font. If you need a more flexible solution, specify groupTemplate. In Angular and Vue, you can declare it in the markup. In React, you can use a render function or component as shown in the following example:
Angular
HTML
TypeScript
<dx-select-box
[dataSource]="selectBoxDataSource"
[grouped]="true"
groupTemplate="group"
displayExpr="name"
valueExpr="count">
<div *dxTemplate="let data of 'group'">
<p>{{data.key}} | Count: {{data.overallCount}}</p>
</div>
</dx-select-box>
import { DxSelectBoxModule } 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 }
]
}];
selectBoxDataSource = 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: [
// ...
DxSelectBoxModule
],
// ...
})Vue
App.vue
<template>
<DxSelectBox ...
:data-source="selectBoxDataSource"
:grouped="true"
display-expr="name"
value-expr="count"
group-template="group"
>
<template #group="{ data }">
<p>
{{ data.key + ' | Count: ' + data.overallCount }}
</p>
</template>
</DxSelectBox>
</template>
<script>
import 'devextreme/dist/css/dx.light.css';
import { DxSelectBox } from 'devextreme-vue/select-box';
import DataSource from "devextreme/data/data_source";
export default {
components: {
DxSelectBox
},
data() {
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 selectBoxDataSource = new DataSource({
store: fruitsVegetables,
map: function(groupedItem) {
let overallCount = 0;
groupedItem.items.forEach(function(item) {
overallCount += item.count;
})
return Object.assign(groupedItem, { overallCount: overallCount });
}
});
return {
selectBoxDataSource
}
}
}
</script>React
App.js
import React from 'react';
import 'devextreme/dist/css/dx.light.css';
import SelectBox from 'devextreme-react/select-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 selectBoxDataSource = new DataSource({
store: fruitsVegetables,
map: function(groupedItem) {
let overallCount = 0;
groupedItem.items.forEach(function(item) {
overallCount += item.count;
})
return Object.assign(groupedItem, { overallCount: overallCount });
}
});
const renderGroup = (data) => {
return (
<p>
{data.key + ' | Count: ' + data.overallCount}
</p>
);
}
class App extends React.Component {
render() {
return (
<SelectBox ...
dataSource={selectBoxDataSource}
grouped="true"
displayExpr="name"
valueExpr="count"
groupRender={renderGroup}
/>
);
}
}
export default App;If you use jQuery, 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 = [{
// ...
// omitted for brevity
// see the AngularJS code
}];
$(function() {
$("#selectBoxContainer").dxSelectBox({
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'
});
});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.
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