场景：父组件发布广播，所有订阅了消息的子组件均可以收到消息

实现：

        创建service： WorkerService.component.ts

import { EventEmitter, Injectable, } from "@angular/core";
@Injectable({
    providedIn: 'platform'
})
export class WorkerService {
    constructor() { }
    public eventbus: EventEmitter<any> = new EventEmitter<any>();
}

        发布消息：（父组件）

import { WorkerService } from './service/WorkerService.component';
export class Parent {
    constructor(private _workerService: WorkerService) { };

    sendMsg() {
        this._workerService.eventbus.emit({ type: "parent ", msg: "父组件广播的消息"})
    }
}

注：发消息时，为方便子组件判断接收到的消息类型，及时做出相应的动作，建议发送的消息为JSON类型，用type作为判断依据，当然，你也可以任意定义发送的消息

        接收消息：（已订阅的子组件）

import { WorkerService } from "./service/WorkerService.component";
export class Children_first {
    constructor(private _workervice: WorkerService) {
        this._workervice.eventbus.subscribe(_event => {
            // _event为父组件广播时传出的参数
            if (_event.type == "parent") {
                console.log(_event.msg)
            }
        })
    }
}

import { WorkerService } from "./service/WorkerService.component";
export class Children_second {
    constructor(private _workervice: WorkerService) {
        this._workervice.eventbus.subscribe(_event => {
            if (_event.type == "parent") {
                console.log(_event.msg)
            }
        })
    }
}

注：所有已订阅的子组件都可以收到消息