Angular2路由问题和ngOnInit调用两次

我有一个非常奇怪的问题,Angular 2路由到我正在路由的组件中的ngOnInit被调用两次,浏览器中的路由被重新设置为原始路由.

我在MaintenanceModule中有一个NotificationListComponent和一个NotificationEditComponent.

在我的根AppModule中,我设置RouterModule将任何未映射的路由重定向到/ maintenance / list.

app.module.ts：

@NgModule({
  declarations: [
    AppComponent
  ],imports: [
    BrowserModule,HttpModule,RouterModule.forRoot([
      {path: "",redirectTo: "maintenance/list",pathMatch: "full"},{path: "**",pathMatch: "full"}
    ],{useHash: true}),CoreModule.forRoot({notificationUrl: "http://localhost:8080/notification-service/notifications"}),MaintenanceModule
  ],providers: [NotificationService],bootstrap: [AppComponent]
})
export class AppModule { }

并且我的MaintenanceModule中定义了/ maintenance / list路由,它指向我的NotificationListComponent,以及一个指向我的NotificationEditComponent的/ maintenance / edit /：id路由.

maintenance.module.ts：

@NgModule({
  imports: [
    CommonModule,RouterModule.forChild([
      {path: "maintenance/list",component: NotificationListComponent,pathMatch: 'full'},{path: "maintenance/edit/:id",component: NotificationEditComponent,pathMatch: 'full'}
    ]),FormsModule
  ],declarations: [
    NotificationListComponent,NotificationEditComponent
  ]
})
export class MaintenanceModule {}

当我的应用程序加载时,它正确地遵循/ maintenance / list路由,我可以在列表中看到我的所有通知.对于列表中的每个通知,都有一个编辑图标,它的点击事件绑定到我的NotificationListComponent中的edit(id：number)方法

通知-list.component.ts：

@Component({
  templateUrl: 'notification-list.component.html'
})
export class NotificationListComponent implements OnInit {

  notifications: Notification[];
  errorMessage: string;

  constructor(private _notificationService: NotificationService,private _router: Router) {}

  ngOnInit(): void {
    this._notificationService.getNotifications()
      .subscribe(
        notifications => this.notifications = notifications,error => this.errorMessage = <any>error);
  }

  clearError(): void {
    this.errorMessage = null;
  }
}

通知-list.component.html：

<div class="row">
  <h1>Notification Maintenance</h1>

  <div *ngIf="errorMessage" class="alert-box alert">
    <span>{{errorMessage}}</span>
    <a class="right" (click)="clearError()">&times;</a>
  </div>

  <p-dataTable [value]="notifications" [sortField]="'code'" [responsive]="true" [sortOrder]="1" [rows]="10" [paginator]="true" [rowsPerPageOptions]="[10,50,100]">
    <p-header>Available Notifications</p-header>
    <p-column [field]="'code'" [header]="'Code'" [sortable]="true" [style]="{'width':'10%'}"></p-column>
    <p-column [field]="'name'" [header]="'Name'" [sortable]="true" [style]="{'width':'40%'}"></p-column>
    <p-column [field]="'roles'" [header]="'Roles'" [style]="{'width':'40%'}"></p-column>
    <p-column [field]="'notificationId'" [header]="'Edit'" [style]="{'width':'10%'}">
      <template let-row="rowData" pTemplate="body">
        <a [routerLink]="'/maintenance/edit/' + row['notificationId']"><span class="fa fa-pencil fa-2x"></span></a>
      </template>
    </p-column>
  </p-dataTable>
</div>

您可以看到,编辑(id：number)方法应该导航到/ maintenance / edit /：id路由.当我点击图标导航到该路由时,浏览器会在地址栏中闪烁正确的路由(例如localhost：4200 /#/ maintenance / edit / 2),但是地址栏中的路由会立即更改为localhost： 4200 /#/维护/列表.即使路由返回到/维护/列表中的地址栏,我的NotificationEditComponent在实际的应用程序仍然可见.但是,我可以看到ngOnInit方法在我的NotificationEditComponent中被调用了两次,因为该id被记录到控制台两次,如果我在ngOnInit函数中放置了一个断点,它会将该断点点击两次.

通知-edit.component.ts：

@Component({
  templateUrl: "notification-edit.component.html"
})
export class NotificationEditComponent implements OnInit{

  notification: Notification;
  errorMessage: string;

  constructor(private _notificationService: NotificationService,private _route: ActivatedRoute,private _router: Router) {
  }

  ngOnInit(): void {
    let id = +this._route.snapshot.params['id'];
    console.log(id);
    this._notificationService.getNotification(id)
      .subscribe(
        notification => this.notification = notification,error => this.errorMessage = <any>error
      );
  }
}

这似乎也是导致其他问题,因为当尝试使用例如[(ngModel)] =“notification.notificationId”将输入值绑定到NotificationEditComponent中的值时,该值不会显示在屏幕上,即使我可以使用Augury chrome扩展名,以及将对象记录到控制台,该值将填充到组件中.

通知-edit.component.html：

<div class="row">
  <h1>Notification Maintenance</h1>

  <div *ngIf="errorMessage" class="alert-box alert">
    <span>{{errorMessage}}</span>
    <a class="right" (click)="clearError()">&times;</a>
  </div>

  <p-fieldset [legend]="'Edit Notification'">
    <label for="notificationId">ID:
      <input id="notificationId" type="number" disabled [(ngModel)]="notification.notificationId"/>
    </label>
  </p-fieldset>

</div>

有没有人知道为什么会发生这种情况？

更新：

我删除了对NotificationService的调用,并将其替换为只是一些模拟数据,然后路由开始工作！但是,一旦我添加了对我的服务的电话,我得到了上面我描述的相同的问题.我甚至删除了CoreModule,只是将该服务直接添加到我的MaintenanceModule中,并且每当我使用实际的服务而不是只是模拟数据时,仍然会遇到同样的问题.

notification.service.ts：

@Injectable()
export class NotificationService {
  private _notificationUrl : string = environment.servicePath;

  constructor(private _http: Http) {
  }

  getNotifications(): Observable<Notification[]> {
    return this._http.get(this._notificationUrl)
      .map((response: Response) => <Notification[]>response.json())
      .catch(this.handleGetError);
  }

  getNotification(id: number): Observable<Notification> {
    return this._http.get(this._notificationUrl + "/" + id)
      .map((response: Response) => <Notification>response.json())
      .catch(this.handleGetError);
  }

  postNotification(notification: Notification): Observable<number> {
    let id = notification.notificationId;
    let requestUrl = this._notificationUrl + (id ? "/" + id : "");
    return this._http.post(requestUrl,notification)
      .map((response: Response) => <number>response.json())
      .catch(this.handlePostError);
  }

  private handleGetError(error: Response) {
    console.error(error);
    return Observable.throw('Error retrieving existing notification(s)!');
  }

  private handlePostError(error: Response) {
    console.error(error);
    return Observable.throw('Error while attempting to save notification!');
  }
}

而且服务似乎运行正常 – 我可以看到端点成功返回数据,当我看到我的NotificationEditComponent与Augury铬扩展时,我可以看到数据看起来正确.但是,模板中不会显示数据,并且仍然显示/ maintenance / edit /：id路由的模板,URL中的路由返回到/ maintenance / list.

更新2：

根据@ user3249448的建议,我将以下内容添加到我的AppComponent进行一些调试：

constructor(private _router: Router) {
  this._router.events.pairwise().subscribe((event) => {
    console.log(event);
  });
}

以下是当我点击“编辑”链接之一时的输出：

TypeError: Cannot read property 'notificationId' of undefined
    at CompiledTemplate.proxyViewClass.View_NotificationEditComponent0.detectChangesInternal (/MaintenanceModule/NotificationEditComponent/component.ngfactory.js:487:49)
    at CompiledTemplate.proxyViewClass.AppView.detectChanges (http://localhost:4200/vendor.bundle.js:80125:14)
    at CompiledTemplate.proxyViewClass.DebugAppView.detectChanges (http://localhost:4200/vendor.bundle.js:80320:44)
    at CompiledTemplate.proxyViewClass.AppView.internalDetectChanges (http://localhost:4200/vendor.bundle.js:80110:18)
    at CompiledTemplate.proxyViewClass.View_NotificationEditComponent_Host0.detectChangesInternal (/MaintenanceModule/NotificationEditComponent/host.ngfactory.js:29:19)
    at CompiledTemplate.proxyViewClass.AppView.detectChanges (http://localhost:4200/vendor.bundle.js:80125:14)
    at CompiledTemplate.proxyViewClass.DebugAppView.detectChanges (http://localhost:4200/vendor.bundle.js:80320:44)
    at ViewRef_.detectChanges (http://localhost:4200/vendor.bundle.js:60319:20)
    at RouterOutlet.activate (http://localhost:4200/vendor.bundle.js:65886:42)
    at ActivateRoutes.placeComponentIntoOutlet (http://localhost:4200/vendor.bundle.js:24246:16)
    at ActivateRoutes.activateRoutes (http://localhost:4200/vendor.bundle.js:24213:26)
    at http://localhost:4200/vendor.bundle.js:24149:58
    at Array.forEach (native)
    at ActivateRoutes.activateChildRoutes (http://localhost:4200/vendor.bundle.js:24149:29)
    at ActivateRoutes.activate (http://localhost:4200/vendor.bundle.js:24123:14)

<p-fieldset [legend]="'Edit Notification'" *ngIf="notification">