Angular 2 Component communication by service not working -

i trying communicate between 2 components service it's not working me, , don't understand why. please guide me through this. want change page title bar when change page.

service

import {injectable} '@angular/core'; import {subject} 'rxjs/subject'; @injectable() export class updatepagetitleservice {   // observable string sources   private newtitlesource = new subject<any>();   // observable string streams   newtitle$ = this.newtitlesource.asobservable();    changetitle(title: any) {     this.newtitlesource.next(title);     console.log(this.newtitlesource);   }   } 

page component

import {component, oninit} '@angular/core';  import {updatepagetitleservice} '../../../../share/updatepagetitle.service';  @component({   selector: 'customer-details',   template: require('./customerdetails.html'),   styleurls: ['./customerdetails.scss'],   providers: [updatepagetitleservice] })   export class customerdetails implements oninit {    constructor(private _updatepagetitleservice: updatepagetitleservice) {    }    ngoninit() {     this._updatepagetitleservice.changetitle('details');   }  } 

title page component

import {component} '@angular/core';  import {updatepagetitleservice} '../../../share/updatepagetitle.service';  @component({   selector: 'ba-content-top',   styles: [require('./titlepage.scss')],   template: require('./titlepage.html'),   providers: [updatepagetitleservice] }) export class titlepage {    public activepagetitle: string = '';    constructor(private _updatepagetitleservice: updatepagetitleservice) {      console.log("sankl");     this.subscription = this._updatepagetitleservice.newtitle$.subscribe(       title => {         console.log("title 1 " + title);         this.activepagetitle = title;       });   }  } 

1. don't add service in @component.providers. cause each component own instance. instead put in @ngmodule.providers of appmodule. make singleton.

2. use behaviorsubject in service instead of vanilla subject if want value cached. see further angular 2 special observables (subject / behaviour subject / replaysubject)