angularjs - Angular 2 Observables and Change detection - How to get one component to retrieve a value, set by another component in a service? -

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i think i'm overlooking fundamental, , i've been banging head couple of days now. i'm new angular , reactive programming.

so, have 1 service , 2 components.

in versionservice.ts have helper method allows components set currentversion in _datastore.

private _datastore: {     currentversion: }; currversionstream$: subject<version>;  constructor(public http: http) {     this.currversionstream$ = new behaviorsubject<version>(null);     this._datastore = {         currentversion: null     }; } public setcurrentversion(v: version): void {     if (v != null) {         this._datastore.currentversion = v;                     this.currversionstream$.next(this._datastore.currentversion);     } }

then in component select-version.component.ts, through (click) event view/template, use setcurrentversion helper method versionservice.ts store cliked on version.

in select.version.template.html:

<ul class="dropdown-menu" aria-labelledby="dropdownmenu1">     <li *ngfor="#v of availableversions" (click)="selectedversion(v)">         <a href="#">             version {{v.versionid}}         </a>     </li>     <li><a href="#">no version</a></li> </ul>

in version.component.ts: here call on method in service. update: inject versionservice in both of components.

    import {versionservice} '../../services/services';  @component({         selector: 'select-version',         templateurl: 'app/component/selectversion/select-version.template.html',         providers: [versionservice]     })  export class selectversioncomponent implements oninit {      constructor(public versionservice: versionservice) {}      public selectedversion(v: version) {         console.log("svc - set version: " + v.versionid);         this.versionservice.setcurrentversion(v);     }

so, in second component want retrieve value set/stored in service (_datastore), , display in view/template (of second component)

in second-component.template.html:

<h2>{{selectedversion}}</h2>

in second-component.ts: update:

    import {versionservice} '../../services/services';  @component({     selector: 'main-container',     templateurl: 'app/component/maincontainer/main-container.template.html',     providers: [versionservice], })  selectedversion: any;  constructor(public versionservice: versionservice) {     this.versionservice.currversionstream$.subscribe((v) => {         if(v != null) {             this.selectedversion = "version" + v.versionid         }     }, error => console.error (error)); }

update: in main component, app.component.ts:

import {sidebarcomponent} './component/sidebar/sidebar.component'; import {maincontainercomponent} './component/maincontainer/main-container.component';   @component({     selector: 'init-app',     templateurl: 'app/app-component.template.html',     directives: [sidebarcomponent, maincontainercomponent], })  export class appcomponent {     constructor() {} }

in boot.ts:

import {bootstrap}    'angular2/platform/browser' import {appcomponent} './app.component' import {http_providers} 'angular2/http'  bootstrap(appcomponent, [http_providers])      .catch(err => console.error(err));

what missing able view currentversion in template of second component, , update each time new value set? reply!

to complement eric , pixelbits said, don't share same instance of service. 1 instance created per component since use providers attribute @ level.

if want know more hierarchical injection, have @ answer:

hope helps you, thierry


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