Angular 4共享服务可观察到的行为主题 [英] Angular 4 Shared Service Observable Behavior Subject

问题描述

我有一个BehaviorSubject作为SharedServices模块的一部分，该模块在Providers部分中提供给AppModule，并在AppComponent中进行订阅.我还在另一个模块AdminModule的另一个组件中订阅了它，但是除非将其添加到AppComponent的Providers部分中，否则我不会获得更改.为什么是这样?我以为如果将其添加到模块"的提供者"部分并订阅所有订阅者，将获得更改?

我必须对子组件执行此操作才能获取更改.我对此感到非常困惑.

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
  providers : [ AppsSharedService]    <--------

解决方案

您可能要遵循Angular文档的指导，然后将此全局提供程序从该共享"模块移至核心"模块:

https://angular.io/guide/ngmodule#no-shared -module-providers

我怀疑这里发生的事情是该服务创建了两次，因此一次发生的更改不会全部反映出来.

I have an BehaviorSubject as part of a SharedServices Module that is provided to the AppModule in the Providers section of the module and subscribe to it in the AppComponent. I also subscribe to it in another component that is part of another Module AdminModule but I'm not getting the changes unless I add it to it Providers section of the AppComponent. Why is this? I thought if you add it to the Providers section in the Module and subscribe all subscribers would get the changes?

I have to do this for the child components to get the changes. I'm really confused by this.

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
  providers : [ AppsSharedService]    <--------

解决方案

You might want to follow the guidance of the Angular docs and move this global provider out of that "shared" module and into a "core" module:

https://angular.io/guide/ngmodule#no-shared-module-providers

I suspect what's happening here is the service is created twice, so changes that are happening in one aren't reflected in all.

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