React Lookup - Handle Value Change

To handle changes to the Lookup component's value, specify the onValueChanged function. This demo uses it to display a picture and text for the selected item.

The Lookup component applies the selected value instantly. If you want users to click the Apply button instead, set the applyValueMode property to "useButtons". It adds the Apply button to the component's drop-down menu. This demo does not show this functionality.

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TS JS

Backend API

import React, { useCallback, useState } from 'react'; import { Lookup, DropDownOptions, LookupTypes } from 'devextreme-react/lookup'; import { SelectBox } from 'devextreme-react'; import { SelectBoxTypes } from 'devextreme-react/select-box'; import { employees, applyValueModeLabel, lookupLabel } from './data.ts'; const applyValueModes = ['instantly', 'useButtons']; const getDisplayExpr = (item: { FirstName: string; LastName: string; }) => (item ? `${item.FirstName} ${item.LastName}` : ''); function App() { const [selectedValue, setSelectedValue] = useState(null); const [applyValueMode, setApplyValueMode] = useState<LookupTypes.ApplyValueMode>('instantly'); const onValueChanged = useCallback((e: LookupTypes.ValueChangedEvent) => { setSelectedValue(e.value); }, [setSelectedValue]); const changeApplyValueMode = useCallback((e: SelectBoxTypes.ValueChangedEvent) => { setApplyValueMode(e.value); }, [setApplyValueMode]); return ( <div> <div className="dx-fieldset"> <div className="dx-field"> <Lookup value={selectedValue} items={employees} displayExpr={getDisplayExpr} placeholder="Select employee" inputAttr={lookupLabel} onValueChanged={onValueChanged} applyValueMode={applyValueMode} > <DropDownOptions showTitle={false} /> </Lookup> </div> </div> {selectedValue && ( <div className="selected"> <div className="frame"> <img src={selectedValue.Picture} /> </div> <div id="selected-employee-notes">{selectedValue.Notes}</div> </div> )} <div className="options"> <div className="caption">Options</div> <div className="option"> <div className="label">Apply Value Mode</div> <SelectBox items={applyValueModes} inputAttr={applyValueModeLabel} value={applyValueMode} onValueChanged={changeApplyValueMode} /> </div> </div> </div> ); } export default App;

import React, { useCallback, useState } from 'react'; import { Lookup, DropDownOptions } from 'devextreme-react/lookup'; import { SelectBox } from 'devextreme-react'; import { employees, applyValueModeLabel, lookupLabel } from './data.js'; const applyValueModes = ['instantly', 'useButtons']; const getDisplayExpr = (item) => (item ? `${item.FirstName} ${item.LastName}` : ''); function App() { const [selectedValue, setSelectedValue] = useState(null); const [applyValueMode, setApplyValueMode] = useState('instantly'); const onValueChanged = useCallback( (e) => { setSelectedValue(e.value); }, [setSelectedValue], ); const changeApplyValueMode = useCallback( (e) => { setApplyValueMode(e.value); }, [setApplyValueMode], ); return ( <div> <div className="dx-fieldset"> <div className="dx-field"> <Lookup value={selectedValue} items={employees} displayExpr={getDisplayExpr} placeholder="Select employee" inputAttr={lookupLabel} onValueChanged={onValueChanged} applyValueMode={applyValueMode} > <DropDownOptions showTitle={false} /> </Lookup> </div> </div> {selectedValue && ( <div className="selected"> <div className="frame"> <img src={selectedValue.Picture} /> </div> <div id="selected-employee-notes">{selectedValue.Notes}</div> </div> )} <div className="options"> <div className="caption">Options</div> <div className="option"> <div className="label">Apply Value Mode</div> <SelectBox items={applyValueModes} inputAttr={applyValueModeLabel} value={applyValueMode} onValueChanged={changeApplyValueMode} /> </div> </div> </div> ); } export default App;

import React from 'react'; import ReactDOM from 'react-dom'; import App from './App.tsx'; ReactDOM.render( <App />, document.getElementById('app'), );

export const employees = [{ ID: 1, FirstName: 'John', LastName: 'Heart', Prefix: 'Mr.', Position: 'CEO', Picture: '../../../../images/employees/01.png', BirthDate: '1964/03/16', HireDate: '1995/01/15', Notes: 'John has been in the Audio/Video industry since 1990. He has led DevAv as its CEO since 2003.\r\n\r\nWhen not working hard as the CEO, John loves to golf and bowl. He once bowled a perfect game of 300.', Address: '351 S Hill St.', }, { ID: 2, FirstName: 'Olivia', LastName: 'Peyton', Prefix: 'Mrs.', Position: 'Sales Assistant', Picture: '../../../../images/employees/09.png', BirthDate: '1981/06/03', HireDate: '2012/05/14', Notes: 'Olivia loves to sell. She has been selling DevAV products since 2012. \r\n\r\nOlivia was homecoming queen in high school. She is expecting her first child in 6 months. Good Luck Olivia.', Address: '807 W Paseo Del Mar', }, { ID: 3, FirstName: 'Robert', LastName: 'Reagan', Prefix: 'Mr.', Position: 'CMO', Picture: '../../../../images/employees/03.png', BirthDate: '1974/09/07', HireDate: '2002/11/08', Notes: 'Robert was recently voted the CMO of the year by CMO Magazine. He is a proud member of the DevAV Management Team.\r\n\r\nRobert is a championship BBQ chef, so when you get the chance ask him for his secret recipe.', Address: '4 Westmoreland Pl.', }, { ID: 4, FirstName: 'Greta', LastName: 'Sims', Prefix: 'Ms.', Position: 'HR Manager', Picture: '../../../../images/employees/04.png', BirthDate: '1977/11/22', HireDate: '1998/04/23', Notes: "Greta has been DevAV's HR Manager since 2003. She joined DevAV from Sonee Corp.\r\n\r\nGreta is currently training for the NYC marathon. Her best marathon time is 4 hours. Go Greta.", Address: '1700 S Grandview Dr.', }, { ID: 5, FirstName: 'Brett', LastName: 'Wade', Prefix: 'Mr.', Position: 'IT Manager', Picture: '../../../../images/employees/05.png', BirthDate: '1968/12/01', HireDate: '2009/03/06', Notes: 'Brett came to DevAv from Microsoft and has led our IT department since 2012.\r\n\r\nWhen he is not working hard for DevAV, he coaches Little League (he was a high school pitcher).', Address: '1120 Old Mill Rd.', }, { ID: 6, FirstName: 'Sandra', LastName: 'Johnson', Prefix: 'Mrs.', Position: 'Controller', Picture: '../../../../images/employees/06.png', BirthDate: '1974/11/15', HireDate: '2005/05/11', Notes: "Sandra is a CPA and has been our controller since 2008. She loves to interact with staff so if you've not met her, be certain to say hi.\r\n\r\nSandra has 2 daughters both of whom are accomplished gymnasts.", Address: '4600 N Virginia Rd.', }, { ID: 7, FirstName: 'Kevin', LastName: 'Carter', Prefix: 'Mr.', Position: 'Shipping Manager', Picture: '../../../../images/employees/07.png', BirthDate: '1978/01/09', HireDate: '2009/08/11', Notes: 'Kevin is our hard-working shipping manager and has been helping that department work like clockwork for 18 months.\r\n\r\nWhen not in the office, he is usually on the basketball court playing pick-up games.', Address: '424 N Main St.', }, { ID: 8, FirstName: 'Cynthia', LastName: 'Stanwick', Prefix: 'Ms.', Position: 'HR Assistant', Picture: '../../../../images/employees/08.png', BirthDate: '1985/06/05', HireDate: '2008/03/24', Notes: 'Cindy joined us in 2008 and has been in the HR department for 2 years. \r\n\r\nShe was recently awarded employee of the month. Way to go Cindy!', Address: '2211 Bonita Dr.', }, { ID: 9, FirstName: 'Kent', LastName: 'Samuelson', Prefix: 'Dr.', Position: 'Ombudsman', Picture: '../../../../images/employees/02.png', BirthDate: '1972/09/11', HireDate: '2009/04/22', Notes: 'As our ombudsman, Kent is on the front-lines solving customer problems and helping our partners address issues out in the field. He is a classically trained musician and is a member of the Chamber Orchestra.', Address: '12100 Mora Dr', }]; export const applyValueModeLabel = { 'aria-label': 'Apply Value Mode' }; export const lookupLabel = { 'aria-label': 'Lookup' };

import React from 'react'; import ReactDOM from 'react-dom'; import App from './App.js'; ReactDOM.render(<App />, document.getElementById('app'));

export const employees = [ { ID: 1, FirstName: 'John', LastName: 'Heart', Prefix: 'Mr.', Position: 'CEO', Picture: '../../../../images/employees/01.png', BirthDate: '1964/03/16', HireDate: '1995/01/15', Notes: 'John has been in the Audio/Video industry since 1990. He has led DevAv as its CEO since 2003.\r\n\r\nWhen not working hard as the CEO, John loves to golf and bowl. He once bowled a perfect game of 300.', Address: '351 S Hill St.', }, { ID: 2, FirstName: 'Olivia', LastName: 'Peyton', Prefix: 'Mrs.', Position: 'Sales Assistant', Picture: '../../../../images/employees/09.png', BirthDate: '1981/06/03', HireDate: '2012/05/14', Notes: 'Olivia loves to sell. She has been selling DevAV products since 2012. \r\n\r\nOlivia was homecoming queen in high school. She is expecting her first child in 6 months. Good Luck Olivia.', Address: '807 W Paseo Del Mar', }, { ID: 3, FirstName: 'Robert', LastName: 'Reagan', Prefix: 'Mr.', Position: 'CMO', Picture: '../../../../images/employees/03.png', BirthDate: '1974/09/07', HireDate: '2002/11/08', Notes: 'Robert was recently voted the CMO of the year by CMO Magazine. He is a proud member of the DevAV Management Team.\r\n\r\nRobert is a championship BBQ chef, so when you get the chance ask him for his secret recipe.', Address: '4 Westmoreland Pl.', }, { ID: 4, FirstName: 'Greta', LastName: 'Sims', Prefix: 'Ms.', Position: 'HR Manager', Picture: '../../../../images/employees/04.png', BirthDate: '1977/11/22', HireDate: '1998/04/23', Notes: "Greta has been DevAV's HR Manager since 2003. She joined DevAV from Sonee Corp.\r\n\r\nGreta is currently training for the NYC marathon. Her best marathon time is 4 hours. Go Greta.", Address: '1700 S Grandview Dr.', }, { ID: 5, FirstName: 'Brett', LastName: 'Wade', Prefix: 'Mr.', Position: 'IT Manager', Picture: '../../../../images/employees/05.png', BirthDate: '1968/12/01', HireDate: '2009/03/06', Notes: 'Brett came to DevAv from Microsoft and has led our IT department since 2012.\r\n\r\nWhen he is not working hard for DevAV, he coaches Little League (he was a high school pitcher).', Address: '1120 Old Mill Rd.', }, { ID: 6, FirstName: 'Sandra', LastName: 'Johnson', Prefix: 'Mrs.', Position: 'Controller', Picture: '../../../../images/employees/06.png', BirthDate: '1974/11/15', HireDate: '2005/05/11', Notes: "Sandra is a CPA and has been our controller since 2008. She loves to interact with staff so if you've not met her, be certain to say hi.\r\n\r\nSandra has 2 daughters both of whom are accomplished gymnasts.", Address: '4600 N Virginia Rd.', }, { ID: 7, FirstName: 'Kevin', LastName: 'Carter', Prefix: 'Mr.', Position: 'Shipping Manager', Picture: '../../../../images/employees/07.png', BirthDate: '1978/01/09', HireDate: '2009/08/11', Notes: 'Kevin is our hard-working shipping manager and has been helping that department work like clockwork for 18 months.\r\n\r\nWhen not in the office, he is usually on the basketball court playing pick-up games.', Address: '424 N Main St.', }, { ID: 8, FirstName: 'Cynthia', LastName: 'Stanwick', Prefix: 'Ms.', Position: 'HR Assistant', Picture: '../../../../images/employees/08.png', BirthDate: '1985/06/05', HireDate: '2008/03/24', Notes: 'Cindy joined us in 2008 and has been in the HR department for 2 years. \r\n\r\nShe was recently awarded employee of the month. Way to go Cindy!', Address: '2211 Bonita Dr.', }, { ID: 9, FirstName: 'Kent', LastName: 'Samuelson', Prefix: 'Dr.', Position: 'Ombudsman', Picture: '../../../../images/employees/02.png', BirthDate: '1972/09/11', HireDate: '2009/04/22', Notes: 'As our ombudsman, Kent is on the front-lines solving customer problems and helping our partners address issues out in the field. He is a classically trained musician and is a member of the Chamber Orchestra.', Address: '12100 Mora Dr', }, ]; export const applyValueModeLabel = { 'aria-label': 'Apply Value Mode' }; export const lookupLabel = { 'aria-label': 'Lookup' };

<!DOCTYPE html> <html lang="en"> <head> <title>DevExtreme Demo</title> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=5.0" /> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/24.1.6/css/dx.light.css" /> <link rel="stylesheet" type="text/css" href="styles.css" /> <script src="https://unpkg.com/core-js@2.6.12/client/shim.min.js"></script> <script src="https://unpkg.com/systemjs@0.21.3/dist/system.js"></script> <script type="text/javascript" src="config.js"></script> <script type="text/javascript"> System.import("./index.tsx"); </script> </head> <body class="dx-viewport"> <div class="demo-container"> <div id="app"></div> </div> </body> </html>

.selected { margin-left: 20px; } .frame { height: 64px; width: 64px; float: left; border: 1px solid #eee; border-radius: 50%; overflow: hidden; margin-right: 20px; } .frame > img { max-width: 64px; } #selected-employee-notes { overflow: hidden; } .dx-field > .dx-lookup { flex: 1; } .dx-fieldset, .selected { margin-right: 320px; } .options { padding: 20px; background-color: rgba(191, 191, 191, 0.15); position: absolute; right: 0; top: 0; bottom: 0; width: 260px; } .caption { font-weight: 500; font-size: 18px; } .option { margin-top: 10px; }