Data Binding in React Dropdown List

4 Sep 202624 minutes to read

The React Dropdown List loads data from local sources or remote services using the dataSource property. It supports both array and DataManager data types.

The component also supports various data services including OData, OData V4, and Web API, with support for XML, JSON, and JSONP formats through DataManager adaptors.

Field	Type	Description
text	string	Specifies the display text of each list item.
value	number or string	Specifies the hidden data value mapped to each list item; should be unique.
groupBy	string	Specifies the category under which the list item has to be grouped.
iconCss	string	Specifies the icon class of each list item.
disabled	boolean	Specifies whether the item is disabled and cannot be selected.

Binding local data

The React Dropdown List can bind to local data in three forms: arrays of primitive values, arrays of objects, and arrays of nested objects. Use fields when the source is an array of objects so text, value, and other display properties can be resolved.

Array of primitive data

The React Dropdown List supports loading arrays of primitive data such as strings and numbers. In this case, the value and text fields are derived from the same item.

[Class-component]

index.jsx

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 {
    // define the array of string
    sportsData = ['Badminton', 'Cricket', 'Football', 'Golf', 'Tennis'];
    render() {
        return (
        // specifies the tag for render the DropDownList component
        <DropDownListComponent id="ddlelement" dataSource={this.sportsData} placeholder="Select a game"/>);
    }
}
ReactDOM.render(<App />, document.getElementById('sample'));

index.tsx

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<{}, {}> {

    // define the array of string
    private sportsData: string[] = ['Badminton', 'Cricket', 'Football', 'Golf', 'Tennis'];

    public render() {
        return (
              // specifies the tag for render the DropDownList component
            <DropDownListComponent id="ddlelement" dataSource={this.sportsData} placeholder="Select a game" />
        );
    }
}
ReactDOM.render(<App />, document.getElementById('sample'));

[Functional-component]

index.jsx

import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
function App() {
    // define the array of string
    const sportsData = ['Badminton', 'Cricket', 'Football', 'Golf', 'Tennis'];
    return (
    // specifies the tag for render the DropDownList component
    <DropDownListComponent id="ddlelement" dataSource={sportsData} placeholder="Select a game"/>);
}
ReactDOM.render(<App />, document.getElementById('sample'));

index.tsx

import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';

function App() {
    // define the array of string
    const sportsData: string[] = ['Badminton', 'Cricket', 'Football', 'Golf', 'Tennis'];

    return (
    // specifies the tag for render the DropDownList component
        <DropDownListComponent id="ddlelement" dataSource={sportsData} placeholder="Select a game" />
    );
}
ReactDOM.render(<App />, document.getElementById('sample'));

Array of objects

The React Dropdown List generates list items from arrays of objects. Map the appropriate columns to the fields property.

In the following example, the Id column is mapped to the value field and the Game column is mapped to the text field.

[Class-component]

index.jsx

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 {
    // define the JSON of data
    sportsData = [
        { Id: 'game1', Game: 'Badminton' },
        { Id: 'game2', Game: 'Football' },
        { Id: 'game3', Game: 'Tennis' }
    ];
    // maps the appropriate column to fields property
    fields = { text: 'Game', value: 'Id' };
    render() {
        return (
        // specifies the tag for render the DropDownList component
        <DropDownListComponent id="ddlelement" dataSource={this.sportsData} fields={this.fields} placeholder="Select a game"/>);
    }
}
ReactDOM.render(<App />, document.getElementById('sample'));

index.tsx

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<{}, {}> {

    // define the JSON of data
    private sportsData: { [key: string]: Object }[] = [
        { Id: 'game1', Game: 'Badminton' },
        { Id: 'game2', Game: 'Football' },
        { Id: 'game3', Game: 'Tennis' }
    ];

    // maps the appropriate column to fields property
    private fields: object = { text: 'Game', value: 'Id' };

    public render() {
        return (
             // specifies the tag for render the DropDownList component
            <DropDownListComponent id="ddlelement" dataSource={this.sportsData} fields={this.fields} placeholder="Select a game" />
        );
    }
}
ReactDOM.render(<App />, document.getElementById('sample'));

[Functional-component]

index.jsx

import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
function App() {
    // define the JSON of data
    const sportsData = [
        { Id: 'game1', Game: 'Badminton' },
        { Id: 'game2', Game: 'Football' },
        { Id: 'game3', Game: 'Tennis' }
    ];
    // maps the appropriate column to fields property
    const fields = { text: 'Game', value: 'Id' };
    return (
    // specifies the tag for render the DropDownList component
    <DropDownListComponent id="ddlelement" dataSource={sportsData} fields={fields} placeholder="Select a game"/>);
}
ReactDOM.render(<App />, document.getElementById('sample'));

index.tsx

import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';

function App() {

    // define the JSON of data
    const sportsData: { [key: string]: Object }[] = [
        { Id: 'game1', Game: 'Badminton' },
        { Id: 'game2', Game: 'Football' },
        { Id: 'game3', Game: 'Tennis' }
    ];

    // maps the appropriate column to fields property
    const fields: object = { text: 'Game', value: 'Id' };

    return (
    // specifies the tag for render the DropDownList component
        <DropDownListComponent id="ddlelement" dataSource={sportsData} fields={fields} placeholder="Select a game" />
    );
}
ReactDOM.render(<App />, document.getElementById('sample'));

Array of complex data

The React Dropdown List generates list items from arrays of complex objects by mapping nested properties to the fields property.

In the following example, Code.Id is mapped to the value field and Country.Name is mapped to the text field.

[Class-component]

index.jsx

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 {
    // define the JSON of data
    countriesData = [
        { Country: { Name: 'Australia' }, Code: { Id: 'AU' } },
        { Country: { Name: 'Bermuda' }, Code: { Id: 'BM' } },
        { Country: { Name: 'Canada' }, Code: { Id: 'CA' } },
        { Country: { Name: 'Cameroon' }, Code: { Id: 'CM' } },
        { Country: { Name: 'Denmark' }, Code: { Id: 'DK' } },
        { Country: { Name: 'France' }, Code: { Id: 'FR' } }
    ];
    // maps the appropriate column to fields property
    fields = { text: 'Country.Name', value: 'Code.Id' };
    render() {
        return (
        // specifies the tag for render the DropDownList component
        <DropDownListComponent id="ddlelement" dataSource={this.countriesData} fields={this.fields} placeholder="Select a country"/>);
    }
}
ReactDOM.render(<App />, document.getElementById('sample'));

index.tsx

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<{}, {}> {

    // define the JSON of data
    private countriesData: { [key: string]: Object }[] = [
        { Country: { Name: 'Australia' }, Code: { Id: 'AU' }},
        { Country: { Name: 'Bermuda' },Code: { Id: 'BM' }},
        { Country:{ Name: 'Canada'}, Code:{ Id: 'CA'} },
        { Country:{Name: 'Cameroon'}, Code:{ Id: 'CM'} },
        { Country:{Name: 'Denmark'}, Code:{ Id: 'DK' }},
        { Country:{Name: 'France'}, Code: { Id:'FR'} }
    ];

    // maps the appropriate column to fields property
    private fields: object = { text: 'Country.Name', value: 'Code.Id' };

    public render() {
        return (
             // specifies the tag for render the DropDownList component
            <DropDownListComponent id="ddlelement" dataSource={this.countriesData} fields={this.fields} placeholder="Select a country" />
        );
    }
}
ReactDOM.render(<App />, document.getElementById('sample'));

[Functional-component]

index.jsx

import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
function App() {
    // define the JSON of data
    const countriesData = [
        { Country: { Name: 'Australia' }, Code: { Id: 'AU' } },
        { Country: { Name: 'Bermuda' }, Code: { Id: 'BM' } },
        { Country: { Name: 'Canada' }, Code: { Id: 'CA' } },
        { Country: { Name: 'Cameroon' }, Code: { Id: 'CM' } },
        { Country: { Name: 'Denmark' }, Code: { Id: 'DK' } },
        { Country: { Name: 'France' }, Code: { Id: 'FR' } }
    ];
    // maps the appropriate column to fields property
    const fields = { text: 'Country.Name', value: 'Code.Id' };
    return (
    // specifies the tag for render the DropDownList component
    <DropDownListComponent id="ddlelement" dataSource={countriesData} fields={fields} placeholder="Select a country"/>);
}
ReactDOM.render(<App />, document.getElementById('sample'));

index.tsx

import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';

function App() {

    // define the JSON of data
    const countriesData: { [key: string]: Object }[] = [
        { Country: { Name: 'Australia' }, Code: { Id: 'AU' }},
        { Country: { Name: 'Bermuda' },Code: { Id: 'BM' }},
        { Country:{ Name: 'Canada'}, Code:{ Id: 'CA'} },
        { Country:{Name: 'Cameroon'}, Code:{ Id: 'CM'} },
        { Country:{Name: 'Denmark'}, Code:{ Id: 'DK' }},
        { Country:{Name: 'France'}, Code: { Id:'FR'} }
    ];

    // maps the appropriate column to fields property
    const fields: object = { text: 'Country.Name', value: 'Code.Id' };

    return (
    // specifies the tag for render the DropDownList component
        <DropDownListComponent id="ddlelement" dataSource={countriesData} fields={fields} placeholder="Select a country" />
    );
}
ReactDOM.render(<App />, document.getElementById('sample'));

Binding remote data

The React Dropdown List supports retrieval of data from remote data services with the help of the DataManager component. The Query property is used to fetch data from the database and bind it to the React Dropdown List.

The following sample displays the first 6 contacts from the “Customers” table of the Northwind Data Service.

[Class-component]

index.jsx

// import DataManager related classes
import { DataManager, ODataV4Adaptor, Query } from '@syncfusion/ej2-data';
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 {
    // bind the DataManager instance to dataSource property
    customerData = new DataManager({
        adaptor: new ODataV4Adaptor,
        crossDomain: true,
        url: 'https://services.odata.org/V4/Northwind/Northwind.svc/'
    });
    // bind the Query instance to query property
    query = new Query().from('Customers').select(['ContactName', 'CustomerID']).take(6);
    // maps the appropriate column to fields property
    fields = { text: 'ContactName', value: 'CustomerID' };
    // sort the resulted items
    sortOrder = 'Ascending';
    render() {
        return (
        // specifies the tag for render the DropDownList component
        <DropDownListComponent id="ddlelement" query={this.query} dataSource={this.customerData} fields={this.fields} sortOrder={this.sortOrder} placeholder="Select a customer"/>);
    }
}
ReactDOM.render(<App />, document.getElementById('sample'));

index.tsx

// import DataManager related classes
import { DataManager, ODataV4Adaptor, Query } from '@syncfusion/ej2-data';
import { SortOrder } from '@syncfusion/ej2-lists';
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<{}, {}> {
    // bind the DataManager instance to dataSource property
    private customerData: DataManager = new DataManager({
      adaptor: new ODataV4Adaptor,
      crossDomain: true,
        url: 'https://services.odata.org/V4/Northwind/Northwind.svc/'
    });
    // bind the Query instance to query property
    private query: Query = new Query().from('Customers').select(['ContactName', 'CustomerID']).take(6);
    // maps the appropriate column to fields property
    private fields: object = { text: 'ContactName', value: 'CustomerID' };
    // sort the resulted items
    private sortOrder: SortOrder = 'Ascending';

    public render() {
        return (
              // specifies the tag for render the DropDownList component
            <DropDownListComponent id="ddlelement" query={this.query} dataSource={this.customerData}
            fields={this.fields} sortOrder={this.sortOrder} placeholder="Select a customer" />
        );
    }
}
ReactDOM.render(<App />, document.getElementById('sample'));

[Functional-component]

index.jsx

// import DataManager related classes
import { DataManager, ODataV4Adaptor, Query } from '@syncfusion/ej2-data';
import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
function App() {
    // bind the DataManager instance to dataSource property
    const customerData = new DataManager({
        adaptor: new ODataV4Adaptor,
        crossDomain: true,
        url: 'https://services.odata.org/V4/Northwind/Northwind.svc/'
    });
    // bind the Query instance to query property
    const query = new Query().from('Customers').select(['ContactName', 'CustomerID']).take(6);
    // maps the appropriate column to fields property
    const fields = { text: 'ContactName', value: 'CustomerID' };
    // sort the resulted items
    const sortOrder = 'Ascending';
    return (
    // specifies the tag for render the DropDownList component
    <DropDownListComponent id="ddlelement" query={query} dataSource={customerData} fields={fields} sortOrder={sortOrder} placeholder="Select a customer"/>);
}
ReactDOM.render(<App />, document.getElementById('sample'));

index.tsx

// import DataManager related classes
import { DataManager, ODataV4Adaptor, Query } from '@syncfusion/ej2-data';
import { SortOrder } from '@syncfusion/ej2-lists';
import { DropDownListComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';

function App() {
    // bind the DataManager instance to dataSource property
    const customerData: DataManager = new DataManager({
      adaptor: new ODataV4Adaptor,
      crossDomain: true,
        url: 'https://services.odata.org/V4/Northwind/Northwind.svc/'
    });
    // bind the Query instance to query property
    const query: Query = new Query().from('Customers').select(['ContactName', 'CustomerID']).take(6);
    // maps the appropriate column to fields property
    const fields: object = { text: 'ContactName', value: 'CustomerID' };
    // sort the resulted items
    const sortOrder: SortOrder = 'Ascending';
    return (
    // specifies the tag for render the DropDownList component
    <DropDownListComponent id="ddlelement" query={query} dataSource={customerData}
        fields={fields} sortOrder={sortOrder} placeholder="Select a customer" />
    );
}
ReactDOM.render(<App />, document.getElementById('sample'));

See Also

• How to load data using template
• How to group the data using header
• How to filter the bound data
• How to get the count of the data when using remote data
• How to achieve cascading
• How to add item in between the options
• How to remove an item
• How to preselect the items in React Dropdown List