javascript - Angular 4 在两个不相关的组件之间传递数据

Question

我对在 Angular 中传递数据有疑问。

首先，我没有 <parent><child [data]=parent.data></child></parent> 这样的结构

我的结构是

<container>
  <navbar>
    <summary></summary>
    <child-summary><child-summary>
  </navbar>
  <content></content>
</container>

所以，在 <summary />我有一个选择将值发送到 <child-summary />和 <content /> .

OnSelect 方法在 <summary /> 内用 (change) 很好地触发了组件。

所以，我尝试使用 @Input , @Output和 @EventEmitter指令，但我看不到如何将事件检索为组件的@Input，除非继续父/子模式。我创建的所有示例都与组件之间存在关系。

编辑:BehaviorSubject 不工作的示例(所有连接到 API 的服务都运行良好，只有 observable 在开始时触发，但在 select 值更改时不触发)

shared service = company.service.ts(用于检索公司数据)

import { Injectable } from '@angular/core';
import { Headers, Http, Response } from '@angular/http';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/toPromise';

@Injectable()
export class SrvCompany {

    private accountsNumber = new BehaviorSubject<string[]>([]);
    currentAccountsNumber = this.accountsNumber.asObservable();

    changeMessage(accountsNumber: string[]) {
        this.accountsNumber.next(accountsNumber);
    }

    private _companyUrl = 'api/tiers/';

    constructor(private http: Http) { }

    getSociete(): Promise<Response> {
        let url = this._companyUrl;
        return this.http.get(url).toPromise();
    }
}

invoice.component.ts(“ child ”)

import { Component, OnInit, Input } from '@angular/core';
import { Headers, Http, Response } from '@angular/http';

import { SrvInvoice } from './invoice.service';
import { SrvCompany } from '../company/company.service';

@Component({
    selector: 'invoice',
    templateUrl: 'tsScripts/invoice/invoice.html',
    providers: [SrvInvoice, SrvCompany]
})

export class InvoiceComponent implements OnInit  {

    invoice: any;

    constructor(private srvInvoice: SrvInvoice, private srvCompany: SrvCompany)
    {

    }

    ngOnInit(): void {
        //this.getInvoice("F001");

        // Invoice data is linked to accounts number from company.
        this.srvCompany.currentAccountsNumber.subscribe(accountsNumber => {
            console.log(accountsNumber);
            if (accountsNumber.length > 0) {
                this.srvInvoice.getInvoice(accountsNumber).then(data => this.invoice = data.json());
            }
        });
    }

    //getInvoice(id: any) {
    //    this.srvInvoice.getInvoice(id).then(data => this.invoice = data.json());
    //}
}

company.component.ts(触发“父级”)

import { Component, Inject, OnInit, Input } from '@angular/core';
import { Headers, Http, Response } from '@angular/http';

import { SrvCompany } from './company.service';

@Component({
    selector: 'company',
    templateUrl: 'tsScripts/company/company.html',
    providers: [SrvCompany]    
})

export class CompanyComponent implements OnInit {

    societes: any[];    
    soc: Response[]; // debug purpose
    selectedSociete: any;

    ville: any;
    ref: any;
    cp: any;
    accountNumber: any[];

    constructor(private srvSociete: SrvCompany)
    {

    }

    ngOnInit(): void {
        this.getSocietes();
    }

    getSocietes(): void {

        this.srvSociete.getSociete()
            .then(data => this.societes = data.json())
            .then(data => this.selectItem(this.societes[0].Id));
    }

    selectItem(value: any) {
        this.selectedSociete = this.societes.filter((item: any) => item.Id === value)[0];
        this.cp = this.selectedSociete.CodePostal;
        this.ville = this.selectedSociete.Ville;
        this.ref = this.selectedSociete.Id;
        this.accountNumber = this.selectedSociete.Accounts;
        console.log(this.accountNumber);
        this.srvSociete.changeMessage(this.accountNumber);
    }
}

Answer 1

在这种情况下，您想要使用共享服务，因为您的组件被构造为兄弟和孙子。这是我制作的关于 sharing data between components 的视频示例解决了这个确切的问题。

首先在服务中创建一个 BehaviorSubject

import { Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';
@Injectable()
export class DataService {

  private messageSource = new BehaviorSubject("default message");
  currentMessage = this.messageSource.asObservable();

  constructor() { }

  changeMessage(message: string) {
    this.messageSource.next(message)
  }

}

然后将此服务注入(inject)每个组件并订阅可观察对象。

import { Component, OnInit } from '@angular/core';
import { DataService } from "../data.service";
@Component({
  selector: 'app-parent',
  template: `
    {{message}}
  `,
  styleUrls: ['./sibling.component.css']
})
export class ParentComponent implements OnInit {

  message:string;

  constructor(private data: DataService) { }

  ngOnInit() {
    this.data.currentMessage.subscribe(message => this.message = message)
  }

}

您可以更改任一组件的值，即使您没有父/子关系，该值也会更新。

import { Component, OnInit } from '@angular/core';
import { DataService } from "../data.service";
@Component({
  selector: 'app-sibling',
  template: `
    {{message}}
    <button (click)="newMessage()">New Message</button>
  `,
  styleUrls: ['./sibling.component.css']
})
export class SiblingComponent implements OnInit {

  message:string;

  constructor(private data: DataService) { }

  ngOnInit() {
    this.data.currentMessage.subscribe(message => this.message = message)
  }

  newMessage() {
    this.data.changeMessage("Hello from Sibling")
  }

}