无法订阅 BehaviorSubject

Question

我有一个奇怪的问题。我在一项服务中定义了 BehaviourSubject 以在用户更改语言时传播更改。在许多组件中，当 BehaviourSubject 更改时，我会做一些事情。它适用于除一个组件之外的所有组件，我不知道为什么。

我的代码：

@Injectable()
export class I18nLanguagesService {
  private activeLang: I18NLanguage = LANGUAGES.find(ln => ln.name === 'Español');
  activeLangSubject = new BehaviorSubject<I18NLanguage>(null);

  setActiveLang(language: I18NLanguage): void {
    this.activeLang = language;
    this.activeLangSubject.next(language);
  }

  getActiveLang(): I18NLanguage {
    return this.activeLang;
  }

  getLanguages(): I18NLanguage[] {
    return LANGUAGES;
  }

}

在CoreModule的providers节中声明，在app.module中导入一次。

用法：

Component 1 (defined in shared.module)

这个很好用。每次主题发出一个值时，它都会调用服务。

 constructor(private statesServ: StatesService, private i18nSrv: I18nLanguagesService) {}
 this.i18nSrv.activeLangSubject
      .pipe(
        tap(() => {
          this.statesMultiCtrl.reset();
          console.log('SELECTOR | In tap')
        }),
        switchMapTo(this.statesServ.getStatesList())
      )
      .subscribe(states => {
        this.states = states;
        this.statesFiltered = this.states;
      });

Pipe (defined in shared.module)

它也适用于管道:

export class AsyncI18nDatePipe implements PipeTransform {
  constructor(private i18nS: I18nLanguagesService) {}

  transform(value: Date | null | undefined, format = 'mediumDate', timezone?: string): Observable<string> {
    if (value) {
      return this.i18nS.activeLangSubject.pipe(map(localeId => formatDate(value, format, localeId.countryCode, timezone)));
    }
    return of('');
  }
}

故障在此组件中，也在 shared.module:

中定义

  constructor(private formBuilder: FormBuilder, private valUsuServ: ValidationUsersService, private cmpServ: CampaignsService, private i18nService: I18nLanguagesService) {
    this.filters = this.formBuilder.group({
      idClient: new FormControl(null),
      idProject: new FormControl({ value: null, disabled: true }),
      sourceLanguage: new FormControl({ value: null, disabled: true }),
      targetLanguage: new FormControl({ value: null, disabled: true }),
      rangeDate: new FormGroup({
        dateFrom: new FormControl(null),
        dateTo: new FormControl(null),
      }),
      idItem: new FormControl({ value: null, disabled: false }),
      searchWords: new FormControl({ value: null, disabled: true }),
      itemState: new FormControl(null),
      category: new FormControl({ value: null, disabled: true }),
      validationUser: new FormControl({ value: null, disabled: true }),
      campaing: new FormControl(null),
      priorityOrd: new FormControl('asc'),
      dateOrd: new FormControl('asc'),
      categoryOrd: new FormControl('asc'),
      campaingOrd: new FormControl('asc'),
    });
  }

  ngOnInit(): void {
    this.i18nService.activeLangSubject.pipe(tap(lang => console.log('FILTERS | In tap -->', lang)));`
}

当我进入有问题的组件时，它会记录所有：

但是当我更改语言时，仅在 'works' 的组件中记录更改：

我不知道为什么会出现这种情况，如有任何帮助，我们将不胜感激。感谢阅读！！

Answer 1

在您的“失败组件”中。尝试订阅更改，例如：

this.i18nService.activeLangSubject.pipe(tap(lang => console.log('FILTERS | In tap -->', lang))).subscribe(() => console.log("changed"));

无法订阅 BehaviorSubject

Unable to subscribe to BehaviourSubject

rxjs

typescript

behaviorsubject

angular