Angular 6 : Component Communication using @Input, @Output and EventEmitter

Angular 6 : Component Communication using @Input, @Output and EventEmitter

Below example is implemented to communicate parent and child component using @Input, @Output and EventEmitter.

Model class

export class country{

    ID : number;

    Name : string;

}

parent.component.ts

import { Component, OnInit } from '@angular/core';

import { country } from 'src/app/Model/Country';

@Component({

  selector: 'app-parent',

  templateUrl: './parent.component.html',

  styleUrls: ['./parent.component.css']

})

export class ParentComponent implements OnInit { 

  name: string = "DemoName";  

  vmCountry: country; 

  receivedChildMessage: string;  

  receivedChildAnotherMessage: country;

  constructor() { }

  ngOnInit() {

    this.vmCountry = new country();

    this.receivedChildAnotherMessage = new country();

    this.vmCountry.Name = "India"; 

  }

  

  getMessage(message: string) {

    this.receivedChildMessage = message; 

  }

  getAnotherMessage(varCountry : country) { 

    this.receivedChildAnotherMessage = varCountry; 

  } 

}

parent.component.html

<h1>

  parent works! test

</h1>

<app-child [name]="name" [varCountry]="vmCountry" 

          (messageToEmit)="getMessage($event)" 

          (anotherMessageToEmit)="getAnotherMessage($event)"></app-child> 

<div class="row">

  <div class="col-md-2">

      {{receivedChildMessage}}

  </div>

  <div class="col-md-2">

      {{receivedChildAnotherMessage.Name}}

    </div>

</div>

child.component.ts

import { Component, OnInit, Input, EventEmitter, Output } from '@angular/core';

import { country } from 'src/app/Model/Country';

@Component({

  selector: 'app-child',

  templateUrl: './child.component.html',

  styleUrls: ['./child.component.css']

})

export class ChildComponent implements OnInit {

  @Input() name: string;

  @Input() varCountry: country;

  @Output() messageToEmit = new EventEmitter<string>();

  @Output() anotherMessageToEmit = new EventEmitter<country>();

   

  constructor() { }

  ngOnInit() {

    

  }

  sendMessageToParent(message: string) {

    this.messageToEmit.emit(message)

  }

  sendAnotherMessageToParent() {

    this.varCountry = new country;

    this.varCountry.ID = 10;

    this.varCountry.Name = "Japan";

    this.anotherMessageToEmit.emit(this.varCountry)

  }

}

child.component.html

<p>

  child works {{name}}!

</p>

<h1>{{varCountry.Name}}</h1>

<div class="row">

  <div class="col-md-2">

    <button (click)="sendMessageToParent('message from child')">Send to Parent</button>

  </div>

  <div class="col-md-2">

    <button (click)="sendAnotherMessageToParent()">Another Send to Parent </button>

  </div>

</div>

app.module.ts

@NgModule({

  declarations: [   

    ParentComponent,

    ChildComponent,

    .....

  ],

  .....

})

Hope this will help you and save your time.

Enjoy !!!

:)