javascript – 带引导事件的Angular2不会触发可观察到的更改

我发现了一个涉及bootstrapjs模态和angular2的奇怪问题.
我有一个绑定到bootstrap模式的html的组件：

// ... lots of imports here

@Component({
selector: 'scrum-sessions-modal',
bindings: [ScrumSessionService, ScrumSessionRepository, ScrumModuleDataContext, ElementRef]

})

@View({
templateUrl: 'templates/modals/scrumSessions.modal.html',

styleUrls: ['']
})

export class ScrumSessionsModalComponent {

    private _elementRef: ElementRef;
    public sessions: ScrumSession[];

    constructor(scrumSessionsProxy: ScrumSessionsProxy, scrumSessionService: ScrumSessionService, elementRef: ElementRef) {

        this._proxy = scrumSessionsProxy;
        this._scrumSessionService = scrumSessionService;
        this._elementRef = elementRef;

        // This is the bootstrap on shown event where i call the initialize method
        jQuery(this._elementRef.nativeElement).on("shown.bs.modal", () => {
            this.initialize();    
        });

         jQuery("#scrumSessionsModal").on("hidden.bs.modal", () => {
             this.cleanup();
         });

    }

    public initialize() {

        // Start our hub proxy to the scrumsessionshub
        this._proxy.start().then(() => {
            // Fetch all active sessions;
            this._scrumSessionService.fetchActiveSessions().then((sessions: ScrumSession[]) => {
                // This console.log is being shown, however the sessions list is never populated in the view even though there are active sessions!
                console.log("loaded");
                this.sessions = sessions;
            }); 
        });
    }

    // Free up memory and stop any event listeners/hubs
    private cleanup() {
        this.sessions = [];
        this._proxy.stop();
    }

}

在这个模态中,我在构造函数中有一个事件监听器,用于检查何时显示模态.当它这样做时,它调用初始化函数,该函数将加载将在模态中显示的初始数据.

模态的html如下所示：

<div class="modal fade" id="scrumSessionsModal" tabindex="-1" role="dialog" aria-labelledby="scrumSessionsModalLabel">
<div class="modal-dialog" role="document">
    <div class="modal-content">
    <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
        <h4 class="modal-title" id="myModalLabel">Actieve sessies </h4>
    </div>
    <div class="modal-body">

        <table class="table">
            <tr>
                <th>Id</th>
                <th>Maker</th>
                <th>Start datum</th>
                <th>Aantal deelnemers</th>
            </tr>
            <tr *ngFor="#session of sessions">
                <td>
                    {{ session.id }}
                </td>
                <td>
                    test
                </td>
                <td>
                    test
                </td>
                <td>
                test
                </td>
            </tr>
        </table>

    </div>
    <div class="modal-footer">
        <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
    </div>
    </div>
</div>

我遇到的问题是由fetchactivesessions函数填充的sessions变量不会在视图中更新.我在调用完成方法上放了一个调试器,并且调用了一个scrumsession对象的结果.

但是,当我删除on(“shown.bs.modal”)事件监听器并简单地将调用初始化()放在5秒的setTimeout函数内,然后打开模态时会正确填充会话列表.

它只发生在我将initialize调用放在bootstrap显示事件的回调中.当调用在jquery回调中时,它就像停止检查更改一样.有谁知道这笔交易是什么？我可以只在构造函数中调用初始化,但我宁愿调用bootstrap中显示的事件.

我已经发布了最新版本的应用程序,用于调试：http://gbscrumboard.azurewebsites.net/

解决方法:

通过易于使用的服务包含在解决方案之上：

更新：如果您使用的是rxjs-6,则需要进行重大更改

import { fromEvent } from 'rxjs';
..

并使用

..
fromEvent(document, BsEventsService.BS_COLLAPSIBLE_SHOWN);

代替

Observable.fromEvent(document, BsEventsService.BS_COLLAPSIBLE_SHOWN);

BS-events.service.ts

import { Subject, Observable, Subscription } from 'rxjs';
import { Injectable } from '@angular/core';

@Injectable() export class BsEventsService {   private static BS_COLLAPSIBLE_SHOWN: string = 'shown.bs.collapse';   private static BS_COLLAPSIBLE_HIDDEN: string = 'hidden.bs.collapse';

  constructor() {
    this.registerEvent(BsEventsService.BS_COLLAPSIBLE_SHOWN);
    this.registerEvent(BsEventsService.BS_COLLAPSIBLE_HIDDEN);
  }

  onCollapsibleShown(): Observable<Event> {
      return Observable.fromEvent(document, BsEventsService.BS_COLLAPSIBLE_SHOWN);
  }   
  onCollapsibleHidden(): Observable<Event> {
      return Observable.fromEvent(document, BsEventsService.BS_COLLAPSIBLE_HIDDEN);
  }

  private registerEvent(event) {
    var script = document.createElement('script');
    script.innerHTML = "eventRelay('" + event + "');"
    document.body.appendChild(script);
  }

}

的index.html

<app-root></app-root>
..
  <!-- relay bootstrap events to angular - start -->
  <script>
    function eventRelay(bs_event) {
      $('body').on(bs_event, function ($event) {
        const customEvent = document.createEvent('Event');
        customEvent.initEvent(bs_event, true, true);
        let target_id = '#' + $event.target.id;
        $(target_id)[0].dispatchEvent(customEvent);
      });
    }
  </script>
  <!-- relay bootstrap events to angular - end -->
..
</body>

零件

import { BsEventsService } from './service/bs-events.service';
import { Subject, Observable, Subscription } from 'rxjs';
..

private onCllapsibleShownSubject: Subscription;
private onCllapsibleHiddenSubject: Subscription;

..
constructor(.., private bsEventsService: BsEventsService) {
..
}

ngOnInit() {
    this.onCllapsibleShownSubject = this.bsEventsService.onCollapsibleShown().subscribe((event: any) => {
      console.log('shown: ' + event.target.id);
    });
    this.onCllapsibleHiddenSubject = this.bsEventsService.onCollapsibleHidden().subscribe((event: any) => {
      console.log('hidden: ' + event.target.id);
    });
}
ngOnDestroy() {
    this.onCllapsibleShownSubject.unsubscribe();
    this.onCllapsibleHiddenSubject.unsubscribe();
}

原文地址：https://codeday.me/bug/20190717/1488552.html