时间：2021-04-21 09:36:59 | 栏目：AngularJS | 点击：次
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();
}
}