Virtualization in React Listview component
5 Jan 202423 minutes to read
UI virtualization loads only viewable list items in a view port which will increase ListView performance on loading large number of data.
Module injection
In order to use UI Virtualization, we need to inject its virtualization
service in the App. This modules should be injected into the ListView using the Inject
directive as like the below code snippet.
import { ListViewComponent, Inject, Virtualization } from '@syncfusion/ej2-react-lists';
....
....
return (
// specifies the tag to render the ListView component
<ListViewComponent id='ui-list' dataSource={listData} enableVirtualization={true} >
<Inject services={[Virtualization]} />
</ListViewComponent>
);
return (
// specifies the tag to render the ListView component
<ListViewComponent id='ui-list' dataSource={listData} enableVirtualization={true}>
<Inject services={[Virtualization]}/>
</ListViewComponent>);
export {};
Getting started
UI virtualization can be enabled in ListView by setting enableVirtualization
property to true. It has two type of scroller
Window scroll - This scroller is used in ListView by default.
Container scroll - This will be used, if the height property of ListView was set.
import * as React from 'react';
import * as ReactDOM from "react-dom";
import { ListViewComponent, Inject, Virtualization } from '@syncfusion/ej2-react-lists';
function App() {
// define the array of Json
let listData;
listData = [
{ text: "Nancy", id: "0" },
{ text: "Andrew", id: "1" },
{ text: "Janet", id: "2" },
{ text: "Margaret", id: "3" },
{ text: "Steven", id: "4" },
{ text: "Laura", id: "5" },
{ text: "Robert", id: "6" },
{ text: "Michael", id: "7" },
{ text: "Albert", id: "8" },
{ text: "Nolan", id: "9" }
];
for (let i = 10; i <= 1010; i++) {
let index = parseInt((Math.random() * 10).toString());
listData.push({ text: listData[index].text, id: i.toString() });
}
return (
// specifies the tag to render the ListView component
<ListViewComponent id="ui-list" dataSource={listData} enableVirtualization={true}>
<Inject services={[Virtualization]}/>
</ListViewComponent>);
}
export default App;
ReactDOM.render(<App />, document.getElementById('element'));
import * as React from 'react';
import * as ReactDOM from "react-dom";
import { ListViewComponent, Inject, Virtualization } from '@syncfusion/ej2-react-lists';
function App() {
// define the array of Json
let listData: { [key: string]: string | object }[];
listData = [
{ text: "Nancy", id: "0" },
{ text: "Andrew", id: "1" },
{ text: "Janet", id: "2" },
{ text: "Margaret", id: "3" },
{ text: "Steven", id: "4" },
{ text: "Laura", id: "5" },
{ text: "Robert", id: "6" },
{ text: "Michael", id: "7" },
{ text: "Albert", id: "8" },
{ text: "Nolan", id: "9" }
];
for (let i: number = 10; i <= 1010; i++) {
let index: number = parseInt((Math.random() * 10).toString());
listData.push({ text: listData[index].text, id: i.toString() });
}
return (
// specifies the tag to render the ListView component
<ListViewComponent id="ui-list" dataSource={listData} enableVirtualization={true}>
<Inject services={[Virtualization]} />
</ListViewComponent>
);
}
export default App;
ReactDOM.render(<App />, document.getElementById('element'));
We can use template
property to customize list items in UI virtualization.
import * as React from 'react';
import * as ReactDOM from "react-dom";
import { ListViewComponent, Inject, Virtualization } from '@syncfusion/ej2-react-lists';
function App() {
// define the array of Json
let listData;
listData = [
{ name: 'Nancy', icon: 'N', id: '0', },
{ name: 'Andrew', icon: 'A', id: '1' },
{ name: 'Janet', icon: 'J', id: '2' },
{ name: 'Margaret', imgUrl: 'https://ej2.syncfusion.com/react/demos/src/listview/images/margaret.png', id: '3' },
{ name: 'Steven', icon: 'S', id: '4' },
{ name: 'Laura', imgUrl: 'https://ej2.syncfusion.com/react/demos/src/listview/images/laura.png', id: '5' },
{ name: 'Robert', icon: 'R', id: '6' },
{ name: 'Michael', icon: 'M', id: '7' },
{ name: 'Albert', imgUrl: 'https://ej2.syncfusion.com/react/demos/src/listview/images/albert.png', id: '8' },
{ name: 'Nolan', icon: 'N', id: '9' }
];
for (let i = 10; i <= 1010; i++) {
let index = parseInt((Math.random() * 10).toString());
listData.push({ name: listData[index].name, icon: listData[index].icon, imgUrl: listData[index].imgUrl, id: i.toString() });
}
function template(data) {
return (
<div className="e-list-wrapper e-list-avatar">
<span className={`e-avatar e-avatar-small e-avatar-circle ${data.icon} ${data.imgUrl ? 'hideUI' : 'showUI'}`}>{data.icon}</span>
<img className={`e-avatar e-avatar-circle ${data.imgUrl ? 'showUI' : 'hideUI'}`} src={data.imgUrl ? data.imgUrl : ' '} alt="" />
<span className="e-list-content">{data.name}</span>
</div>
);
} return (
// specifies the tag to render the ListView component
<ListViewComponent id='ui-list' dataSource={listData} enableVirtualization={true} template={template} cssClass='e-list-template' height={500} headerTitle="Contacts" showHeader={true}>
<Inject services={[Virtualization]}/>
</ListViewComponent>);
}
export default App;
ReactDOM.render(<App />, document.getElementById('element'));
import * as React from 'react';
import * as ReactDOM from "react-dom";
import { ListViewComponent, Inject, Virtualization } from '@syncfusion/ej2-react-lists';
function App() {
// define the array of Json
let listData: { [key: string]: string | object }[];
listData = [
{ name: 'Nancy', icon: 'N', id: '0', },
{ name: 'Andrew', icon: 'A', id: '1' },
{ name: 'Janet', icon: 'J', id: '2' },
{ name: 'Margaret', imgUrl: 'https://ej2.syncfusion.com/react/demos/src/listview/images/margaret.png', id: '3' },
{ name: 'Steven', icon: 'S', id: '4' },
{ name: 'Laura', imgUrl: 'https://ej2.syncfusion.com/react/demos/src/listview/images/laura.png', id: '5' },
{ name: 'Robert', icon: 'R', id: '6' },
{ name: 'Michael', icon: 'M', id: '7' },
{ name: 'Albert', imgUrl: 'https://ej2.syncfusion.com/react/demos/src/listview/images/albert.png', id: '8' },
{ name: 'Nolan', icon: 'N', id: '9' }
];
for (let i: number = 10; i <= 1010; i++) {
let index: number = parseInt((Math.random() * 10).toString());
listData.push({ name: listData[index].name, icon: listData[index].icon, imgUrl: listData[index].imgUrl, id: i.toString() });
}
// Set customized list template
function template(data: any) {
return (
<div className="e-list-wrapper e-list-avatar">
<span className={`e-avatar e-avatar-circle ${data.icon} ${data.imgUrl ? 'hideUI' : 'showUI'}`}>{data.icon}</span>
<img className={`e-avatar e-avatar-circle ${data.imgUrl ? 'showUI' : 'hideUI'}`} src={data.imgUrl ? data.imgUrl : ' '} />
<span className="e-list-content">{data.name}</span>
</div>
);
}
return (
// specifies the tag to render the ListView component
<ListViewComponent id='ui-list' dataSource={listData} enableVirtualization={true} template={template} height={500} cssClass='e-list-template' headerTitle="Contacts" showHeader={true}>
<Inject services={[Virtualization]} />
</ListViewComponent>
);
}
export default App;
ReactDOM.render(<App />, document.getElementById('element'));
#ui-list.e-listview {
margin: auto;
max-width: 325px;
line-height: initial;
border: 1px solid lightgray;
}
/* ListView header alignment */
#ui-list.e-listview .e-list-header {
height: 50px
}
#ui-list.e-listview .e-list-header .e-text {
line-height: 18px
}
/* ListView template customization */
#ui-list.e-listview .showUI {
display: flex;
align-items: center;
justify-content: center;
border-radius: 50%;
}
#ui-list.e-listview .hideUI {
display: none;
}
#ui-list.e-listview .e-list-item {
padding: 3px 0;
}
#ui-list.e-listview .R {
background: lightgrey;
}
#ui-list.e-listview .M {
background: pink;
}
#ui-list.e-listview .A {
background: lightgreen;
}
#ui-list.e-listview .S {
background: lightskyblue;
}
#ui-list.e-listview .J {
background: orange;
}
#ui-list.e-listview .N {
background: lightblue;
}
Conditional rendering
We have also provided following conditional rendering support for template and groupTemplate.
Name | Syntax |
---|---|
conditional class | <div class="${ $id % 2 === 0 ? 'even-list' : 'odd-list'}"></div> |
conditional attribute | <div id="${ $id % 2 === 0 ? 'even-list' : 'odd-list'}"></div> |
conditional text content | <div>${ $id % 2 === 0 ? 'even-list' : 'odd-list'}</div> |
In the below sample, we have applied light blue for even list and light coral for odd list based on the conditional class.
import * as React from 'react';
import * as ReactDOM from "react-dom";
import { ListViewComponent, Inject, Virtualization } from '@syncfusion/ej2-react-lists';
function App() {
// define the array of Json
let listData;
listData = [
{ text: "Nancy", id: "0" },
{ text: "Andrew", id: "1" },
{ text: "Janet", id: "2" },
{ text: "Margaret", id: "3" },
{ text: "Steven", id: "4" },
{ text: "Laura", id: "5" },
{ text: "Robert", id: "6" },
{ text: "Michael", id: "7" },
{ text: "Albert", id: "8" },
{ text: "Nolan", id: "9" }
];
for (let i = 10; i <= 1010; i++) {
let index = parseInt((Math.random() * 10).toString());
listData.push({ text: listData[index].text, id: i.toString() });
}
let template = "<div id=\"list-container\" class=\"${ $id % 2 === 0 ? 'even-list' : 'odd-list' }\" > ${text} </div>";
return (
// specifies the tag to render the ListView component
<ListViewComponent id="ui-list" dataSource={listData} enableVirtualization={true} template={template} height={500}>
<Inject services={[Virtualization]}/>
</ListViewComponent>);
}
export default App;
ReactDOM.render(<App />, document.getElementById('element'));
import * as React from 'react';
import * as ReactDOM from "react-dom";
import { ListViewComponent, Inject, Virtualization } from '@syncfusion/ej2-react-lists';
function App() {
// define the array of Json
let listData: { [key: string]: string | object }[];
listData = [
{ text: "Nancy", id: "0" },
{ text: "Andrew", id: "1" },
{ text: "Janet", id: "2" },
{ text: "Margaret", id: "3" },
{ text: "Steven", id: "4" },
{ text: "Laura", id: "5" },
{ text: "Robert", id: "6" },
{ text: "Michael", id: "7" },
{ text: "Albert", id: "8" },
{ text: "Nolan", id: "9" }
];
for (let i: number = 10; i <= 1010; i++) {
let index: number = parseInt((Math.random() * 10).toString());
listData.push({ text: listData[index].text, id: i.toString() });
}
let template: string =
"<div id=\"list-container\" class=\"${ $id % 2 === 0 ? 'even-list' : 'odd-list' }\" > ${text} </div>";
return (
// specifies the tag to render the ListView component
<ListViewComponent
id="ui-list"
dataSource={listData}
enableVirtualization={true}
template={template}
height={500}
>
<Inject services={[Virtualization]} />
</ListViewComponent>
);
}
export default App;
ReactDOM.render(<App />, document.getElementById('element'));