Javascript 错误属性未定义，但存在未定义的检查

我尝试为参与者选择方框。因此，用户将能够向一个或多个参与者发送一些数据。在用户选择一些参与者后，用户将从anuglar材质重定向到模型对话框

所以我有这个：

export class EcheqSelectorComponent implements OnInit, OnDestroy {
  private subscriptions = new Subscription();
  echeqs: EcheqFamilyInfo[] = [];
  allEcheqs: EcheqFamilyInfo[] = [];
  echeqFamily: EcheqFamilyInfo;
  searchInput = '';
  filtering = false;
  participantInfo: ParticipantInfoDTO;
  echeqsToSend: EcheqFamilyInfo[] = [];
  echeqSubmissionBatchDTO: EcheqSubmissionBatchDTO;
  participantIds$: Observable<string[]>;
  patientId: string;

  public participantIds: string[] = [];
  public participantIdsFromRoute: string[] = [];

  constructor(
    private apiService: EcheqDefinitionService,
    private dialog: MatDialogRef<EcheqSelectorComponent>,
    public selectedParticipantService: SelectedParticipantsService,
    private submissionService: EcheqSubmissionMedicalService,
    private snackBar: MatSnackBar,

    @Inject(MAT_DIALOG_DATA) public data: any,
    public dialogRef: MatDialogRef<EcheqSelectorComponent>
  ) {
    this.participantInfo = data.participant;
    this.participantIdsFromRoute = this.data.participant.participantId ? [this.data.participant.participantId] : undefined;
  }

  ngOnInit() {
    this.subscriptions.add(
      this.apiService.listEcheqFamilies().subscribe(families => {
        this.echeqs = families;
        this.allEcheqs = families;
      })
    );
}

说：

EcheqSelectorComponent_Host.ngfactory.js? [sm]:1 ERROR TypeError: Cannot read property 'participantId' of undefined
    at new EcheqSelectorComponent (echeq-selector.component.ts:50)
    at createClass (core.js:18681)
    at createDirectiveInstance (core.js:18550)
    at createViewNodes (core.js:19776)
    at createRootView (core.js:19690)
    at callWithDebugContext (core.js:20722)
    at Object.debugCreateRootView [as createRootView] (core.js:20208)
    at ComponentFactory_.push../node_modules/@angular/core/fesm5/core.js.ComponentFactory_.create (core.js:18029)
    at ComponentFactoryBoundToModule.push../node_modules/@angular/core/fesm5/core.js.ComponentFactoryBoundToModule.create (core.js:7812)
    at ViewContainerRef_.push../node_modules/@angular/core/fesm5/core.js.ViewContainerRef_.createComponent (core.js:18140)

那么我要怎么做才能解决这个问题呢

---

谢谢

问题在于

此.data.participant

未定义。因此，异常实际上是在验证检查期间发生的。从一致性的角度来看，您不应该在一个方法中将

participant

属性设置为一个对象，而在另一个方法中只设置id。这可能就是造成混乱的原因。好的，谢谢你的answare。但是我必须改变什么呢？

this.participantIdsFromRoute = this.data.participant.participantId ? [this.data.participant.participantId] : undefined;
  }

EcheqSelectorComponent_Host.ngfactory.js? [sm]:1 ERROR TypeError: Cannot read property 'participantId' of undefined
    at new EcheqSelectorComponent (echeq-selector.component.ts:50)
    at createClass (core.js:18681)
    at createDirectiveInstance (core.js:18550)
    at createViewNodes (core.js:19776)
    at createRootView (core.js:19690)
    at callWithDebugContext (core.js:20722)
    at Object.debugCreateRootView [as createRootView] (core.js:20208)
    at ComponentFactory_.push../node_modules/@angular/core/fesm5/core.js.ComponentFactory_.create (core.js:18029)
    at ComponentFactoryBoundToModule.push../node_modules/@angular/core/fesm5/core.js.ComponentFactoryBoundToModule.create (core.js:7812)
    at ViewContainerRef_.push../node_modules/@angular/core/fesm5/core.js.ViewContainerRef_.createComponent (core.js:18140)