The DropDownList has built-in support to filter data items when allowFiltering is enabled. The filter
operation starts as soon as you start typing characters in the search box.
To display filtered items in the popup, filter the required data and return it to the DropDownList
via updateData method by using the filtering event.
The following sample illustrates how to query the data source and pass the data to the DropDownList
through the updateData method in filtering event.
// import DataManager related classes
import { Query } from '@syncfusion/ej2-data';
import { DropDownListComponent, FilteringEventArgs } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
export default class App extends React.Component<{}, {}> {
// maps the appropriate column to fields property
private fields: object = { text: "Country", value: "Index" };
// define the filtering data
private searchData: { [key: string]: Object }[] = [
{ Index: "s1", Country: "Alaska" }, { Index: "s2", Country: "California" },
{ Index: "s3", Country: "Florida" }, { Index: "s4", Country: "Georgia" }
];
// filtering event handler to filter a Country
public onFiltering(args: FilteringEventArgs) {
let query = new Query();
// frame the query based on search string with filter type.
query = (args.text !== "") ? query.where("Country", "startswith", args.text, true) : query;
// pass the filter data source, filter query to updateData method.
args.updateData(this.searchData, query);
}
public render() {
return (
// specifies the tag for render the DropDownList component
<DropDownListComponent id="ddlelement" popupHeight="250px" fields={this.fields} filtering={this.onFiltering = this.onFiltering.bind(this)} allowFiltering={true} dataSource={this.searchData} placeholder="Select a country" />
);
}
}
ReactDOM.render(<App />, document.getElementById('sample'));<!DOCTYPE html>
<html lang="en">
<head>
<title>Syncfusion React DropDownList</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="description" content="Essential JS 2 for React Components" />
<meta name="author" content="Syncfusion" />
<link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-inputs/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-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>
<style>
#loader {
color: #008cff;
height: 40px;
left: 45%;
position: absolute;
top: 45%;
width: 30%;
}
</style>
</head>
<body>
<div id='sample' style="margin: 20px auto 0; width:250px;">
<div id='loader'>Loading....</div>
</div>
</body>
</html>When filtering the list items, you can set the limit for character count to raise remote request and fetch filtered data on the DropDownList. This can be done by manual validation within the filter event handler.
In the following example, the remote request does not fetch the search data until the search key contains three characters.
import { DataManager, ODataV4Adaptor, Query } from '@syncfusion/ej2-data';
import { SortOrder } from '@syncfusion/ej2-lists';
import { DropDownListComponent, FilteringEventArgs } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
export default class App extends React.Component<{}, {}> {
// bind the DataManager instance to dataSource property
private searchData: DataManager = new DataManager({
adaptor: new ODataV4Adaptor,
crossDomain: true,
url: 'https://services.odata.org/V4/Northwind/Northwind.svc/Customers'
});
// maps the appropriate column to fields property
private fields: object = { text: 'ContactName', value: 'CustomerID' };
// bind the Query instance to query property
private query: Query = new Query().select(['ContactName', 'CustomerID']).take(7);
// sort the resulted items
private sortOrder: SortOrder = 'Ascending';
// filtering event handler to filter a customer
public onFiltering(e: FilteringEventArgs) {
// load overall data when search key empty.
if (e.text === '') {
e.updateData(this.searchData);
} else {
// restrict the remote request until search key contains 3 characters.
if (e.text.length < 3) { return; }
let query: Query = new Query().select(['ContactName', 'CustomerID']);
query = (e.text !== '') ? query.where('ContactName', 'startswith', e.text, true) : query;
e.updateData(this.searchData, query);
}
}
public render() {
return (
// specifies the tag for render the DropDownList component
<DropDownListComponent id="ddlelement" allowFiltering={true} popupHeight="250px" filtering={this.onFiltering = this.onFiltering.bind(this)} sortOrder={this.sortOrder} query={this.query} dataSource={this.searchData} fields={this.fields} placeholder="Select a customer" />
);
}
}
ReactDOM.render(<App />, document.getElementById('sample'));<!DOCTYPE html>
<html lang="en">
<head>
<title>Syncfusion React DropDownList</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="description" content="Essential JS 2 for React Components" />
<meta name="author" content="Syncfusion" />
<link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-inputs/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-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>
<style>
#loader {
color: #008cff;
height: 40px;
left: 45%;
position: absolute;
top: 45%;
width: 30%;
}
</style>
</head>
<body>
<div id='sample' style="margin: 20px auto 0; width:250px;">
<div id='loader'>Loading....</div>
</div>
</body>
</html>While filtering, you can change the filter type to contains,
startsWith, or endsWith for string type within the filter event handler.
In the following examples, data filtering is done with endsWith type.
// import DataManager related classes
import { Query } from '@syncfusion/ej2-data';
import { SortOrder } from '@syncfusion/ej2-lists';
import { DropDownListComponent, FilteringEventArgs } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
export default class App extends React.Component<{}, {}> {
// bind the DataManager instance to dataSource property
private searchData: { [key: string]: Object }[] = [
{ Index: "s1", Country: "Alaska" }, { Index: "s2", Country: "Californiag" },
{ Index: "s3", Country: "Florida" }, { Index: "s4", Country: "Georgia" }
]
// maps the appropriate column to fields property
private fields: object = { value: "Country" };
// sort the resulted items
private sortOrder: SortOrder = 'Ascending';
// filtering event handler to filter a customer
public onFiltering(e: FilteringEventArgs) {
// load overall data when search key empty.
if (e.text === '') {
e.updateData(this.searchData);
} else {
let query: Query = new Query();
// change the type of filtering
query = (e.text !== '') ? query.where('Country', 'endsWith', e.text, true) : query;
e.updateData(this.searchData, query);
}
}
public render() {
return (
// specifies the tag for render the DropDownList component
<DropDownListComponent id="ddlelement" allowFiltering={true} popupHeight="250px" filtering={this.onFiltering = this.onFiltering.bind(this)} sortOrder={this.sortOrder} dataSource={this.searchData} fields={this.fields} placeholder="Select a customer" />
);
}
}
ReactDOM.render(<App />, document.getElementById('sample'));<!DOCTYPE html>
<html lang="en">
<head>
<title>Syncfusion React DropDownList</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="description" content="Essential JS 2 for React Components" />
<meta name="author" content="Syncfusion" />
<link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-inputs/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-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>
<style>
#loader {
color: #008cff;
height: 40px;
left: 45%;
position: absolute;
top: 45%;
width: 30%;
}
</style>
</head>
<body>
<div id='sample' style="margin: 20px auto 0; width:250px;">
<div id='loader'>Loading....</div>
</div>
</body>
</html>Data items can be filtered either with or without case sensitivity using the DataManager. This can be done
by passing the fourth optional parameter of the where clause.
The following example shows how to perform case-sensitive filter.
import { Query } from '@syncfusion/ej2-data';
import { SortOrder } from '@syncfusion/ej2-lists';
import { DropDownListComponent, FilteringEventArgs } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
export default class App extends React.Component<{}, {}> {
// bind the DataManager instance to dataSource property
private searchData: { [key: string]: Object }[] = [
{ Index: "s1", Country: "Alaska" }, { Index: "s2", Country: "Californiag" },
{ Index: "s3", Country: "Florida" }, { Index: "s4", Country: "Georgia" }
]
// maps the appropriate column to fields property
private fields: object = { value: "Country" };
// sort the resulted items
private sortOrder: SortOrder = 'Ascending';
// filtering event handler to filter a customer
public onFiltering(e: FilteringEventArgs) {
// load overall data when search key empty.
if (e.text === '') {
e.updateData(this.searchData);
} else {
let query: Query = new Query();
// change the type of filtering
query = (e.text !== '') ? query.where('Country', 'contains', e.text, false) : query;
e.updateData(this.searchData, query);
}
}
public render() {
return (
// specifies the tag for render the DropDownList component
<DropDownListComponent id="ddlelement" popupHeight="245px" allowFiltering={true} filtering={this.onFiltering = this.onFiltering.bind(this)} sortOrder={this.sortOrder} dataSource={this.searchData} fields={this.fields} placeholder="Select a customer" />
);
}
}
ReactDOM.render(<App />, document.getElementById('sample'));<!DOCTYPE html>
<html lang="en">
<head>
<title>Syncfusion React DropDownList</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="description" content="Essential JS 2 for React Components" />
<meta name="author" content="Syncfusion" />
<link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-inputs/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-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>
<style>
#loader {
color: #008cff;
height: 40px;
left: 45%;
position: absolute;
top: 45%;
width: 30%;
}
</style>
</head>
<body>
<div id='sample' style="margin: 20px auto 0; width:250px;">
<div id='loader'>Loading....</div>
</div>
</body>
</html>DropDownList supports diacritics filtering which will ignore the diacritics and makes it easier to filter the results in international characters lists when the ignoreAccent is enabled.
In the following sample,data with diacritics are bound as dataSource for DropDownList.
import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
export default class App extends React.Component<{}, {}> {
private countriesData: string[] = [
'Aeróbics',
'Aeróbics en Agua',
'Aerografía',
'Aeromodelaje',
'Águilas',
'Ajedrez',
'Ala Delta',
'Álbumes de Música',
'Alusivos',
'Análisis de Escritura a Mano'];
public render() {
return (
<DropDownListComponent id="diacritics" ignoreAccent={true} dataSource={this.diacriticsData} allowFiltering={true} placeholder="Select a value" filterBarPlaceholder="e.g: aero" />
);
}
}
ReactDOM.render(<App />, document.getElementById('sample'));<!DOCTYPE html>
<html lang="en">
<head>
<title>Syncfusion React DropDownList</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="description" content="Essential JS 2 for React Components" />
<meta name="author" content="Syncfusion" />
<link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-inputs/styles/material.css" rel="stylesheet" />
<link href="//cdn.syncfusion.com/ej2/ej2-react-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>
<style>
#loader {
color: #008cff;
height: 40px;
left: 45%;
position: absolute;
top: 45%;
width: 30%;
}
</style>
</head>
<body>
<div id='sample' style="margin: 20px auto 0; width:250px;">
<div id='loader'>Loading....</div>
</div>
</body>
</html>