부모 클래스에서 자식 구성 요소 메서드 호출-Angular

부모 클래스에서 자식 구성 요소 메서드 호출-Angular

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호출하려는 메서드가있는 자식 구성 요소를 만들었습니다.

이 메서드를 호출하면 console.log()줄만 시작하고 test속성을 설정하지 않습니까 ??

아래는 변경 사항이 적용된 빠른 시작 Angular 앱입니다.

부모의

import { Component } from '@angular/core';
import { NotifyComponent }  from './notify.component';

@Component({
    selector: 'my-app',
    template:
    `
    <button (click)="submit()">Call Child Component Method</button>
    `
})
export class AppComponent {
    private notify: NotifyComponent;

    constructor() { 
      this.notify = new NotifyComponent();
    }

    submit(): void {
        // execute child component method
        notify.callMethod();
    }
}

아이

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

@Component({
    selector: 'notify',
    template: '<h3>Notify {{test}}</h3>'
})
export class NotifyComponent implements OnInit {
   test:string; 
   constructor() { }

    ngOnInit() { }

    callMethod(): void {
        console.log('successfully executed.');
        this.test = 'Me';
    }
}

test속성도 어떻게 설정할 수 있습니까?

---

다음을 사용하여이 작업을 수행 할 수 있습니다 @ViewChild더 많은 정보 확인이에 대한 링크

유형 선택기 포함

@Component({
  selector: 'child-cmp',
  template: '<p>child</p>'
})
class ChildCmp {
  doSomething() {}
}
@Component({
  selector: 'some-cmp',
  template: '<child-cmp></child-cmp>',
  directives: [ChildCmp]
})
class SomeCmp {
  @ViewChild(ChildCmp) child:ChildCmp;
  ngAfterViewInit() {
    // child is set
    this.child.doSomething();
  }
}

문자열 선택기 사용

@Component({
  selector: 'child-cmp',
  template: '<p>child</p>'
})
class ChildCmp {
  doSomething() {}
}
@Component({
  selector: 'some-cmp',
  template: '<child-cmp #child></child-cmp>',
  directives: [ChildCmp]
})
class SomeCmp {
  @ViewChild('child') child:ChildCmp;
  ngAfterViewInit() {
    // child is set
    this.child.doSomething();
  }
}

---

이것은 나를 위해 일했습니다! Angular 2의 경우 부모 구성 요소에서 자식 구성 요소 메서드 호출

Parent.component.ts

    import { Component, OnInit, ViewChild } from '@angular/core';
    import { ChildComponent } from '../child/child'; 
    @Component({ 
               selector: 'parent-app', 
               template: `<child-cmp></child-cmp>` 
              }) 
    export class parentComponent implements OnInit{ 
        @ViewChild(ChildComponent ) child: ChildComponent ; 

        ngOnInit() { 
           this.child.ChildTestCmp(); } 
}

---

Child.component.ts

import { Component } from '@angular/core';
@Component({ 
  selector: 'child-cmp', 
  template: `<h2> Show Child Component</h2><br/><p> {{test }}</p> ` 
})
export class ChildComponent {
  test: string;
  ChildTestCmp() 
  { 
    this.test = "I am child component!"; 
  }
 }

---

---

가장 쉬운 방법은 Subject를 사용하는 것입니다. 아래 예제 코드에서 'tellChild'가 호출 될 때마다 자녀에게 알림이 전송됩니다.

Parent.component.ts

import {Subject} from 'rxjs/Subject';
...
export class ParentComp {
    changingValue: Subject<boolean> = new Subject();
    tellChild(){
    this.changingValue.next(true);
  }
}

Parent.component.html

<my-comp [changing]="changingValue"></my-comp>

Child.component.ts

...
export class ChildComp implements OnInit{
@Input() changing: Subject<boolean>;
ngOnInit(){
  this.changing.subscribe(v => { 
     console.log('value is changing', v);
  });
}

Stackblitz의 작업 샘플

---

user6779899's answer is neat and more generic However, based on the request by Imad El Hitti, a light weight solution is proposed here. This can be used when a child component is tightly connected to one parent only.

Parent.component.ts

export class Notifier {
    valueChanged: (data: number) => void = (d: number) => { };
}

export class Parent {
    notifyObj = new Notifier();
    tellChild(newValue: number) {
        this.notifyObj.valueChanged(newValue); // inform child
    }
}

Parent.component.html

<my-child-comp [notify]="notifyObj"></my-child-comp>

Child.component.ts

export class ChildComp implements OnInit{
    @Input() notify = new Notifier(); // create object to satisfy typescript
    ngOnInit(){
      this.notify.valueChanged = (d: number) => {
            console.log(`Parent has notified changes to ${d}`);
            // do something with the new value 
        };
    }
 }

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Angular – Call Child Component’s Method in Parent Component’s Template

You have ParentComponent and ChildComponent that looks like this.

parent.component.html

parent.component.ts

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

@Component({
  selector: 'app-parent',
  templateUrl: './parent.component.html',
  styleUrls: ['./parent.component.css']
})
export class ParentComponent {
  constructor() {
  }
}

child.component.html

<p>
  This is child
</p>

child.component.ts

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

@Component({
  selector: 'app-child',
  templateUrl: './child.component.html',
  styleUrls: ['./child.component.css']
})
export class ChildComponent {
  constructor() {
  }

  doSomething() {
    console.log('do something');
  }
}

When serve, it looks like this:

When user focus on ParentComponent’s input element, you want to call ChildComponent’s doSomething() method.

Simply do this:

1. Give app-child selector in parent.component.html a DOM variable name (prefix with # – hashtag), in this case we call it appChild.
2. Assign expression value (of the method you want to call) to input element’s focus event.

The result:

참고URL : https://stackoverflow.com/questions/38974896/call-child-component-method-from-parent-class-angular