How to call router outlet child component method from parent comonent

Question

I am new to angular2

I have a button in parent component, if

Answer 1

With child in router-outlet, you can use ContentChild to be able to call a method in the child. So...

import { ContentChild } from '@angular/core';

in your parent:

@ContentChild(ChildComponent)
private childComponent: ChildComponent;

and on your click event do:

this.childComponent.doSomething()

Also you need to add your child component in the providers array in parent:

@Component({
  selector: 'parent',
  ...
  providers: [ChildComponent]
})

Answer 2

I found two ways to achieve this:

1. Injecting the main component into children

You can add an event to your main component, inject the main component to your child components and subscribe to the event. See the plunk that illustrates this. But, now your children have a dependency on your main component. This may be not good.

main component

executeAction: EventEmitter<any> = new EventEmitter();
constructor() { }
performAction() {
  this.executeAction.emit();
}

child

constructor(private appComponent: AppComponent) {
    this.executeAction = this.executeAction.bind(this);
    eventSubscriber(appComponent.executeAction, this.executeAction);
}
ngOnDestroy(): void {
    eventSubscriber(this.appComponent.executeAction, this.executeAction, true);
}
executeAction() {
    alert('1');
}

2. Implementing a service

The best solution here and as described in Parent and children communicate via a service is to create a service that will be an additional layer between the main component and children. In this way, you will be independent from the main component implementation. See the plunk that illustrates this approach.

service

subscription = new Subject();
executeAction() {
    this.subscription.next();
}

main component

constructor(private appService: AppService) { }
performAction() {
  this.appService.executeAction();
}

child

constructor(private appService: AppService) {
    this.executeAction = this.executeAction.bind(this);
    eventSubscriber(appService.subscription, this.executeAction);
}
ngOnDestroy(): void {
    eventSubscriber(this.appService.subscription, this.executeAction, true);
}
executeAction() {
    alert('1');
}

Answer 3

There are two ways to call router outlet child component method from the parent component.

1. ViewChild/ViewChildren - You can use ViewChild/ViewChildren to get the element(s) or the directive(s) matching the selector from the view DOM. It doesn't matter child component is rendered by router outlet.

   import { ViewChild } from '@angular/core'; @ViewChild(HomeComponent) private childComponent: HomeComponent;

Then you can call any method,

this.childComponent.changeTitle();

Demo - call router outlet child component method

2. Shared services - Since angular services are singleton by injecting them to your controllers you can call methods. (Above answers are already mentioned this approach)

Answer 4

This can be achieved by the following way as well:

.html

<parent>
    <router-outlet (activate)="onActivate($event)"><router-outlet>
</parent>

.ts

activatedComponentReference:any

onActivate(activatedComponentReference) {
  this.activatedComponentReference = activatedComponentReference;
}

onBtnClick() {
   const childRouteComp = this.activatedComponentReference as ChildRouteComponent;
   childRouteComp.childFunction();
}

Answer 5

I think Event emitter can do the trick for you

Though you can use it directly in child component also but using a common service here would be a good practice

First you need to create an emitter in a service something like

export class EmitterService {
   public nameEmitter:EventEmitter<string>=new EventEmitter(); 

    //method to get question
    changeName(name:string){   
        this.nameEmitter.emit(name)    
    }

}

Then in root component inject service dependency and call change name method to emit the change

 constructor(private emitter :EmitterService) {}
 this.emitter.changeName("New Name");

And at the end in child component subscribe to changes

this.emitter.nameEmitter.subscribe(name=>{this.name=name})

Here is working plunker

Answer 6

You can use a shared service to communicate with components added by the router.

You can also use the activate event of the Router outlet for the parent to know when a component was added by the router

Template

<router-outlet (activate)="onActivate($event)"></router-outlet>

Component

  onActivate(componentRef){
    componentRef.works();
  }

Child Comp

 works(){
    console.log("works");
  }