我正在尝试使用共享服务的组件创建一个模块 . 一个组件( graphview )具有对BehaviorSubject的可观察对象的订阅 . 另一个组件( chart-type )稍后通过调用服务中的函数( chart-config )来更新BehaviorSubject . 问题是当 ChartTypeComponent
具有服务调用 .next(data)
GraphviewComponent
doesn 't update. I'm时,假设正在使用该服务的多个实例,并且我不确定如何解决它 .
GraphModule
(他们的父模块)在声明中有 ChartTypeComponent
和 GraphviewComponent
,在提供者中有 ChartConfigService
.
chart-config.service.ts 看起来像:
@Injectable()
export class ChartConfigService {
private _chartconfig: BehaviorSubject<any> = new BehaviorSubject<any>({});
public chartconfig = this._chartconfig.asObservable();
private headers = new Headers({ 'Content-Type': 'application/json', 'charset': 'UTF-8' });
private options = new RequestOptions({ headers: this.headers });
constructor(private http: Http) {
http.get('/api/chartconfig/59484e3946f7f059f1e72927')
.map(res => res.json())
.subscribe( data => this._chartconfig.next(data) );
}
getChartConfig(): Observable<any> {
return this.chartconfig;
}
updateChartConfig(option, params) {
this.http.put('/api/chartconfig/59484e3946f7f059f1e72927', '{ ' + JSON.stringify(option) + ': ' + JSON.stringify(params) + ' }' , this.options)
.map(res => res.json())
.subscribe( data => this._chartconfig.next(data) );
}
graphview.component.ts 导入服务和订阅 . 它不提供服务 .
@Component({
selector: 'app-graphview',
templateUrl: './graphview.component.html',
styleUrls: ['./graphview.component.scss']
})
和
constructor(private chartconfigService: ChartConfigService) { }
ngOnInit() {
this.subscription = this.chartconfigService.chartconfig
.subscribe( data => this.localChartConfig = data );
}
chart-type.component.ts 仅导入服务,并调用chartconfigService.updateChartConfig:
@Component({
selector: 'app-chart-type',
templateUrl: './chart-type.component.html',
styleUrls: ['./chart-type.component.scss']
})
和
chartType(param: string) {
this.chartconfigService.updateChartConfig('type', param);
}
我找到了相关的问题和答案:
Delegation: EventEmitter or Observable in Angular2
Angular2 Observable BehaviorSubject service not working
但我可以做错了 . 如何在调用updateChartConfig时更新 graphview.component.ts ?
注意:所有调用/方法/等工作,并且在调用updateChartConfig()之后 this._chartconfig.next(data).getValue()
表明正在服务中正确更新BehaviorSubject . graphview.component.ts根本没有收到新数据 .
Update:
将 GraphviewComponent
s ngOnInit()更改为的结果
ngOnInit() {
this.subscription = this.chartconfigService.chartconfig
.subscribe( data => { this.localChartConfig = data; console.log('in subscription: ' + this.localChartConfig); }, e => console.log('error: ' + e), () => console.log('then: ' + this.localChartConfig) );
}
在控制台中生成:
in subscription: [object Object]
in subscription: [object Object]
但是在OnInit之后永远不会触发(当 ChartTypeComponent
调用updateChartConfig()时) .
Update2: 很明显,root是注入服务,而不是GraphModule:
我仍然希望子模块提供服务,以便它包含在子模块中 .