Hey guys, today in this post we are going to learn about How to define a custom event in child lightning web component and passing values from child component to parent component in — LWC
Files we used in this post example:-
lwcParent.html | Lightning Web Component HTML | Template HTML file for used to write HTML element for user interface. |
lwcParent.js | Lightning Web Component JavaScript | It is holding child component and it’s value. |
lwcParent.js-meta.xml | XML Meta File | It is used for where this lightning web component you want to exposed. |
lwcChild.html | Lightning Web Component HTML | It is child HTML file and calling on lwcParent.html. |
lwcChild.js | Lightning Web Component JavaScript | It is holding @api public property with handler change functionality and it’s calling into parent componet. |
lwcChild.js-meta.xml | XML Meta File | It is used for where this lightning web component should be exposed. |
eventApplwc.app | Lightning Application | It is used for call the parent component to preview on browser. |
Live Demo
Other related post that would you like to learn in LWC
- Do you know:- The cheapest and best smartphone in your budget 2022?
Start lwcParent Component
Step 1:- Create Lightning Web Component : lwcParent.html
SFDX:Lightning Web Component >> New >> lwcParent.html
lwcParent.html [Lightning Web Component HTML]
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 |
<template> <lightning-card title="How to pass value from child to parent component in lwc" icon-name="custom:custom11"> <div class="slds-wrap slds-grid"> <div class="slds-col slds-size_12-of-12 slds-p-horizontal--small slds-m-bottom--medium"> <h3><b>lwcChild Component</b></h3> <c-lwc-child ondemoevent={handleChange}></c-lwc-child> <h3><b>lwcParent Component</b></h3> <b style="color:brown; margin-top:15px;">The Name Value Is:-</b> {currentVal} </div> </div> <br/><br/> <!--Start RelatedTopics Section--> <div style="border:1px #ddd solid; padding:10px; background:#eee; margin:40px 0;"> <p data-aura-rendered-by="435:0"><img src="https://www.w3web.net/wp-content/uploads/2021/05/thumbsUpLike.png" width="25" height="25" style="vertical-align:top; margin-right:10px;" data-aura-rendered-by="436:0"><strong data-aura-rendered-by="437:0"><span style="font-size:16px; font-style:italic; display:inline-block; margin-right:5px;">Don't forget to check out:-</span><a href="https://www.w3web.net/" target="_blank" rel="noopener noreferrer" style="text-decoration:none;" data-aura-rendered-by="440:0">An easy way to learn step-by-step online free Salesforce tutorial, To know more Click <span style="color:#ff8000; font-size:18px;" data-aura-rendered-by="442:0">Here..</span></a></strong></p> <br/><br/> <p data-aura-rendered-by="435:0"><img src="https://www.w3web.net/wp-content/uploads/2021/07/tickMarkIcon.png" width="25" height="25" style="vertical-align:top; margin-right:10px;" data-aura-rendered-by="436:0"><strong data-aura-rendered-by="437:0"><span style="font-size:17px; font-style:italic; display:inline-block; margin-right:5px; color:rgb(255 128 0);">You May Also Like →</span> </strong></p> <div style="display:block; overflow:hidden;"> <div style="width: 50%; float:left; display:inline-block"> <ul style="list-style-type: square; font-size: 16px; margin: 0 0 0 54px; padding: 0;"> <li><a href="https://www.w3web.net/lwc-get-set-lightning-checkbox-value/" target="_blank" rel="noopener noreferrer">How to get selected checkbox value in lwc</a></li> <li><a href="https://www.w3web.net/display-account-related-contacts-in-lwc/" target="_blank" rel="noopener noreferrer">how to display account related contacts based on AccountId in lwc</a></li> <li><a href="https://www.w3web.net/create-lightning-datatable-row-actions-in-lwc/" target="_blank" rel="noopener noreferrer">how to create lightning datatable row actions in lwc</a></li> <li><a href="https://www.w3web.net/if-and-else-condition-in-lwc/" target="_blank" rel="noopener noreferrer">how to use if and else condition in lwc</a></li> <li><a href="https://www.w3web.net/get-selected-radio-button-value-and-checked-default-in-lwc/" target="_blank" rel="noopener noreferrer">how to display selected radio button value in lwc</a></li> </ul> </div> <div style="width: 50%; float:left; display:inline-block"> <ul style="list-style-type: square; font-size: 16px; margin: 0 0 0 54px; padding: 0;"> <li><a href="https://www.w3web.net/display-account-related-contacts-lwc/" target="_blank" rel="noopener noreferrer">display account related contacts based on account name in lwc</a></li> <li><a href="https://www.w3web.net/create-lightning-datatable-row-actions-in-lwc/" target="_blank" rel="noopener noreferrer">how to insert a record of account Using apex class in LWC</a></li> <li><a href="https://www.w3web.net/fetch-picklist-values-dynamic-in-lwc/" target="_blank" rel="noopener noreferrer">how to get picklist values dynamically in lwc</a></li> <li><a href="https://www.w3web.net/edit-save-and-remove-rows-dynamically-in-lightning-component/" target="_blank" rel="noopener noreferrer">how to edit/save row dynamically in lightning component</a></li> <li><a href="https://www.w3web.net/update-parent-object-from-child/" target="_blank" rel="noopener noreferrer">update parent field from child using apex trigger</a></li> </ul> </div> <div style="clear:both;"></div> <br/> <div class="youtubeIcon"> <a href="https://www.youtube.com/channel/UCW62gTen2zniILj9xE6LmOg" target="_blank" rel="noopener noreferrer"><img src="https://www.w3web.net/wp-content/uploads/2021/11/youtubeIcon.png" width="25" height="25" style="vertical-align:top; margin-right:10px;"/> <strong>TechW3web:-</strong> To know more, Use this <span style="color: #ff8000; font-weight: bold;">Link</span> </a> </div> </div> </div> <!--End RelatedTopics Section--> </lightning-card> </template> |
Step 2:- Create Lightning Web Component : lwcParent.js
SFDX:Lightning Web Component >> New >> lwcParent.js
lwcParent.js [LWC JavaScript File]
1 2 3 4 5 6 7 8 |
import {LightningElement,api} from 'lwc'; export default class LwcParent extends LightningElement { @api currentVal; handleChange(event){ this.currentVal=event.detail; //window.console.log('fldInp# ' + this.nameInp); } } |
Step 3:- Create Lightning Web Component : lwcParent.js-meta.xml
SFDX:Lightning Web Component >> New >> lwcParent.js-meta.xml
lwcParent.js-meta.xml [LWC Meta Data XML]
1 2 3 4 5 6 7 8 9 10 11 |
<?xml version="1.0" encoding="UTF-8"?> <LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata"> <apiVersion>45.0</apiVersion> <isExposed>true</isExposed> <targets> <target>lightning__AppPage</target> <target>lightning__RecordPage</target> <target>lightning__HomePage</target> <target>lightning__Tab</target> </targets> </LightningComponentBundle> |
Start lwcChild Component
Step 4:- Create Lightning Web Component : lwcChild.html
SFDX:Lightning Web Component >> New >> lwcChild.html
lwcChild.html [Lightning Web Component HTML]
1 2 3 4 5 6 7 |
<template> <div class="slds-wrap slds-grid"> <div class="slds-col slds-size_12-of-12 slds-p-horizontal--small slds-m-bottom--medium"> <lightning-input type="text" label="Name" name="name" onchange={handleChangeName}></lightning-input> </div> </div> </template> |
Step 5:- Create Lightning Web Component : lwcChild.js
SFDX:Lightning Web Component >> New >> lwcChild.js
lwcChild.js [LWC JavaScript File]
1 2 3 4 5 6 7 8 9 10 11 12 13 14 |
import { LightningElement,api } from 'lwc'; export default class LwcChild extends LightningElement { @api nameInp; handleChangeName(event){ this.nameInp = event.target.value; const myDemoEvent = new CustomEvent('demoevent',{ detail:this.nameInp }); this.dispatchEvent(myDemoEvent); //window.console.log('nameInpBBB' + this.nameInp); } } |
Step 6:- Create Lightning Web Component : lwcChild.js-meta.xml
SFDX:Lightning Web Component >> New >> lwcChild.js-meta.xml
lwcChild.js-meta.xml [LWC Meta Data XML]
1 2 3 4 5 |
<?xml version="1.0" encoding="UTF-8"?> <LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata"> <apiVersion>45.0</apiVersion> <isExposed>true</isExposed> </LightningComponentBundle> |
Start Application Component
Step 7:- Create Lightning Application : eventApplwc.app
From Developer Console >> File >> New >> Lightning Application
eventApplwc.app [Component Application File]
1 2 3 |
<aura:application extends="force:slds"> <c:lwcParent/> </aura:application> |
Further post that would you like to learn in LWC
What is custom event LWC?
Custom events are used for communication in lightning web components. First, the comparison with Aura Components. In Aura component, we need to create a separate event file and need to register the event, where event is fired. LWC uses standard DOM events to create and dispatch events.
What is bubble event in LWC?
When we create an event, bubbles and composed define the event propagation behavior. In this behavior, the event bubbles up the DOM, but don't cross the shadow boundary. In simple terms, It bubbles up inside the current template, in which event is fired, but it would not cross it's boundary.
What is dispatch event?
dispatchEvent is what you call if you want to send or trigger an event. Internally, the browser is doing this whenever the user rotates their device, which triggers orientationchange. In this specific example, you don't need to trigger this manually unless you need to do so for testing.
Related Topics | You May Also Like
- Your reaction of the article ▾
Good work keep it up for sharing such a great knowledge.
Thanks For Sharing The Amazing content. I Will also share with my friends. Great Content thanks a lot.
Ow great i am looking for this article. Thank you so much.
Hi. your post is so nice and I really loved reading your post.
It was very well authored and easy to understand. Great Thanks for sharing awesome info. I really love to read your blog.
Very Nice Article
5 Internet Approval Site (Do Follow Backlinks)
Very Nice Information
Hi. your post is so nice and I really loved reading your post….
Nice toppic
very nice information thanks for sharing
For More information
Superb Great Content Sir Please Keep It Up
https://www.w3web.net/passing-color-code-from-lwc-child-to-aura-component/#comment-1033
Great work, thanks