如何在Angular 6中从父组件调用子组件的方法 [英] How to call child components's method from the parent component in Angular 6

问题描述

父项

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

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

    submit(): void {
        // execute child component method
        // This line is compiled properly but at the run time it gives me error related to the static injector## Heading ##
        childComp.callMethod();
    }
}

子组件

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

@Component({
    selector: 'child',
    template: '<h3>Child component {{test}}</h3>'
})
export class ChildComponent implements OnInit {
   test:string; 
   constructor() { }

    ngOnInit() { }

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

我在使用静态注入器时遇到错误，无法将子组件注入到父组件中.这是错误.

I am getting an error for the static injector, I am not able to inject the child component in the parent component. Here is the error.

StaticInjectorError(AppModule)[AppComponent-> ChildComponent]: StaticInjectorError [ChildComponet]: NullInjectorError:没有为ChildComponet提供程序！

StaticInjectorError(AppModule)[AppComponent -> ChildComponent]: StaticInjectorError[ChildComponet]: NullInjectorError: No provider for ChildComponet!

我在Appmodule中添加了引用，并在声明中添加了组件.不过，我也面临着同样的问题.

I have added the reference in the Appmodule and added the component in the declaration. Still, I am facing the same issue.

请帮助！

推荐答案

更新:

只需像<app-child #child></app-child>那样导出子项，然后 您可以使用child调用所有方法，例如:<button> (click)="child.callMethod()">Call</button>

just export the child like <app-child #child></app-child> and then you can call all methods using child like : <button> (click)="child.callMethod()">Call</button>

Parent.html

<app-child #child></app-child>
<button (click)="child.callMethod()">Call</button>

旧答案

您可以像示例中那样使用Parent的@ViewChild:

You can use @ViewChild by Parent like in example:

父母

import { Component, ViewChild } from '@angular/core';
import { ChildComponent } from './child.component';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  constructor() { }
  @ViewChild(ChildComponent) private myChild: ChildComponent;
  submit() {
    this.myChild.callMethod();
  }
}

孩子:

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

@Component({
  selector: 'child',
  template: `<h3>Child component {{test}}</h3>`
})
export class ChildComponent {
  test = 0;
  callMethod() {
    console.log('successfully executed.');
    this.test++;
  }
}

这是一个工作示例

Here is a worked example

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