A small example of custom event & dispatch event where we define a custom event in child component and passing values from child component to parent component in -- LWC

Post Views: 1,282

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

In LWC communication how to pass the multiple values from parent component to child component through component JavaScript Method in salesforce lightning web component
Find the Lightning Web Component (LWC) UI Developer Guide, Component Reference and Aura Documentation Including Buttons, Icons, Input Fields & Much More..
Creating a Lightning Datatable with Row Actions and Display a Modal Popup on Click View Icon Button in Salesforce Lightning Web Component – LWC
Deleting multiple records dynamically with checkbox on delete button in lightning web component salesforce — LWC
How to add custom style css and change the text color & text size through JavaScript in lightning web component – LWC
How do you use template if:true and template if:false condition to display content in lightning web component – LWC

Start lwcParent Component

Step 1:- Create Lightning Web Component : lwcParent.html

SFDX:Lightning Web Component >> New >> lwcParent.html

lwcParent.html [Lightning Web Component HTML]

  <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>
 
</lightning-card>
</template>

<lightning-card title="How to pass value from child to parent component in lwc" icon-name="custom:custom11">

<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>

</lightning-card>

</template>

Step 2:- Create Lightning Web Component : lwcParent.js

SFDX:Lightning Web Component >> New >> lwcParent.js

lwcParent.js [LWC JavaScript File]

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);        
        }
}

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]

   <?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>

<?xml version="1.0" encoding="UTF-8"?>

<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]

   <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>

<lightning-input type="text" label="Name" name="name" onchange={handleChangeName}></lightning-input>

</div>

</template>

Step 5:- Create Lightning Web Component : lwcChild.js

SFDX:Lightning Web Component >> New >> lwcChild.js

lwcChild.js [LWC JavaScript File]

  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);
   }

}

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]

  <?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
    <apiVersion>45.0</apiVersion>
    <isExposed>true</isExposed>
</LightningComponentBundle>

<?xml version="1.0" encoding="UTF-8"?>

</LightningComponentBundle>

Start Application Component

Step 7:- Create Lightning Application : eventApplwc.app

From Developer Console >> File >> New >> Lightning Application

eventApplwc.app [Component Application File]

   <aura:application extends="force:slds">
   <c:lwcParent/>
</aura:application>

<aura:application extends="force:slds">

<c:lwcParent/>

</aura:application>

Further post that would you like to learn in LWC

5 thoughts on “A small example of custom event & dispatch event where we define a custom event in child component and passing values from child component to parent component in — LWC”

Newspaper jobs

December 7, 2020 at 4:48 am

Good work keep it up for sharing such a great knowledge.
pinjara khubsurti kaa

December 8, 2020 at 12:59 pm

Thanks For Sharing The Amazing content. I Will also share with my friends. Great Content thanks a lot.
Shahriar

December 8, 2020 at 3:58 pm

Ow great i am looking for this article. Thank you so much.
idsbuddy

December 19, 2020 at 9:57 am

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.
Joganiwellness

February 4, 2021 at 9:10 am

Very Nice Article
5 Internet Approval Site (Do Follow Backlinks)

A small example of custom event & dispatch event where we define a custom event in child component and passing values from child component to parent component in — LWC

Files we used in this post example:-

Start lwcParent Component

lwcParent.html [Lightning Web Component HTML]

lwcParent.js [LWC JavaScript File]

lwcParent.js-meta.xml [LWC Meta Data XML]

Start lwcChild Component

lwcChild.html [Lightning Web Component HTML]

lwcChild.js [LWC JavaScript File]

lwcChild.js-meta.xml [LWC Meta Data XML]

Start Application Component

eventApplwc.app [Component Application File]

Related Topics

5 thoughts on “A small example of custom event & dispatch event where we define a custom event in child component and passing values from child component to parent component in — LWC”

Leave a Comment Cancel reply

Files we used in this post example:-

Start lwcParent Component

lwcParent.html [Lightning Web Component HTML]

lwcParent.js [LWC JavaScript File]

lwcParent.js-meta.xml [LWC Meta Data XML]

Start lwcChild Component

lwcChild.html [Lightning Web Component HTML]

lwcChild.js [LWC JavaScript File]

lwcChild.js-meta.xml [LWC Meta Data XML]

Start Application Component

eventApplwc.app [Component Application File]

Related Topics

5 thoughts on “A small example of custom event & dispatch event where we define a custom event in child component and passing values from child component to parent component in — LWC”

Leave a Comment Cancel reply

Please Contribute to Support If Some Value Added in Your Project or Website