Question

我有2个需要通信的组件，中间是一个服务。

服务

responseJSON

组件A

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs/Subject';

@Injectable()
export class CommunicationService {

  // Observable string sources
  private onOpen = new Subject<any>();

  // Observable string streams
  onOpen = this.onOpen.asObservable();

  // Service message commands
  callComponentMethod() {
    this.onOpen.next();
  }

}

组件B

    import { Component } from '@angular/core';
import { CommunicationService } from './communication.service.ts'

@Component({
  selector: 'app-comp1',
  template: `
    <button type="button" (click)="callMethod()">Call method from Component1</button>
  `
})
export class Component1 {

  constructor( private communicationService: CommunicationService  ) { }

  callMethod = function () {
    this.communicationService.onOpen();
  }

}

下面是这个http://plnkr.co/edit/SmntWy0GTNdvGB5Jb3hO?p=preview，该方法被调用，但是，我想传递一个参数。我该怎么做呢？

Answer 1

您的实现中有很多不正确的地方。这是您要实现的目标的工作示例：

Example

您不需要使用Subject，您可以使用常规的可观察对象，然后将新值“推送”到该可观察对象的发射器：

export class CommunicationService {
  // Observable string sources
  private emitter: any;
  public messageInbox: Observable<any>

  constructor(){
     this.messageInbox = Observable.create(e => this.emitter = e);
  }

  // Service message commands
  public SendMessage() {
    this.emitter.next("hello");
  }

您的组件中的代码基本上没问题。

Answer 2

调用$Query = Database::Prepare("SELECT * FROM new_jobs WHERE thickness LIKE ?"); $Query->Execute(array("%".$thickness."%"));类的callComponentMethod函数，而不是调用CommunicationService。其次，如果要传递信息，可以通过将值传递给onOpen函数来实现。

下面是修改后的代码

CommunicationService

callComponentMethod

Component1

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs/Subject';

@Injectable()
export class CommunicationService {

  // Observable string sources
  private onOpen = new Subject<any>();

  // Observable string streams
  onOpen = this.onOpen.asObservable();

  // Service message commands
  callComponentMethod(info:any) {
    this.onOpen.next(info);    //<-- pass the value to subscribers
  }

}

从服务呼叫部件

2 个答案:

CommunicationService

Component1