角度 – 如何订阅事件发射器一次?
发布时间:2020-12-17 07:39:04 所属栏目:安全 来源:网络整理
导读:// Part of servicepublic someEvent: EventEmitternumber = new EventEmitter();....// Component@Component({ selector: 'some-component',template: `...`})export class SomeComponent { constructor(public service: Service) { this.service.someEvent
// Part of service public someEvent: EventEmitter<number> = new EventEmitter(); .... // Component @Component({ selector: 'some-component',template: `...` }) export class SomeComponent { constructor(public service: Service) { this.service.someEvent.subscribe((x) => { // Do something }); } } SomeComponent显示在/ route中.当我在我的应用程序中导航到不同的路由,并再次返回时,SomeComponent将再次订阅该事件,导致回调触发两次.如何订阅事件一次或取消订阅销毁组件并再次订阅? // Can't subscribe after. ngOnDestroy() { this.service.someEvent.unsubscribe(); }
对订阅的呼叫返回
instance of Disposable ,其方法为
dispose .
或者如果您使用的是RxJS 5, 从RxJS docs:
存储您的呼叫结果以订阅,然后在ngOnDestroy中处理订阅. RxJS 5: export class SomeComponent { constructor (public service: Service) { this.subscription = this.service.someEvent.subscribe((x) => {...}); } ngOnDestroy () { this.subscription.unsubscribe(); } } RxJS< 5: export class SomeComponent { constructor (public service: Service) { this.subscription = this.service.someEvent.subscribe((x) => {...}); } ngOnDestroy () { this.subscription.dispose(); } } (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |