angular2 组件之间通过service互相传递

母组件传值给子组件

母组件通过service传值给子组件，很简单，声明一个service

@Injectable()export class ToolbarTitleService {    title:string;}

然后在母组件中依赖注入

@Component({    selector: 'admin',    templateUrl: './admin.component.html',    styleUrls: ['./admin.component.scss'],    providers: [ToolbarTitleService],})

子组件中直接声明即可使用

export class RoleListComponent implements OnInit {    constructor(private toolbarTitleService:ToolbarTitleService) {            console.log(this.toolbarTitleService.title);         }    ngOnInit() { }}

子组件传值给母组件

那么我想反过来传值回去该怎么办，即使我在子组件注入了service，母组件也不会在我修改了servie的值之后得到通知，这时候就需要用到subscribe

service代码：

import { Injectable } from '@angular/core';import { Subject } from 'rxjs/Subject';@Injectable()export class ToolbarTitleService {    private titleSource = new Subject();    //获得一个Observable    titleObservable =this.titleSource.asObservable();    constructor() { }    //发射数据，当调用这个方法的时候，Subject就会发射这个数据，所有订阅了这个Subject的Subscription都会接受到结果    emitTitle(title: string) {        this.titleSource.next(title);    }}

子组件代码：

import { ToolbarTitleService } from './../../common/toolbar-title.service';import { Component, OnInit ,Output,EventEmitter} from '@angular/core';@Component({    selector: 'role-list',    templateUrl: 'role-list.component.html',    styleUrls: ['./role-list.component.css'],    providers: [],})export class RoleListComponent implements OnInit {    constructor(private toolbarTitleService:ToolbarTitleService) {            //调用方法，发射数据            this.toolbarTitleService.emitTitle('角色列表');         }    ngOnInit() { }}

母组件:

import { Component, OnInit } from '@angular/core';import { ToolbarTitleService } from "app/common/toolbar-title.service";import { Subscription } from "rxjs/Subscription";@Component({    selector: 'admin',    templateUrl: './admin.component.html',    styleUrls: ['./admin.component.scss'],    providers: [ToolbarTitleService],})export class AdminComponent implements OnInit {    title: string;    subscription: Subscription;    constructor(private toolbarTitleService: ToolbarTitleService) {        //使用subscribe来订阅，当数据被发射出来的时候,这里就会接收到结果        this.subscription = this.toolbarTitleService.titleObservable.subscribe(src => console.log('得到的title:' + src));    }    ngOnInit() {    }    //销毁的时候需要取消订阅，因为订阅之后会一直处于观察者状态,不取消会导致泄露    ngOnDestroy() {        this.subscription.unsubscribe();    }}