无法读取Object.eval中未定义的属性'gender'[作为updateDirectives]

我正在创建一个社交媒体应用程序，我不确定为什么导航到新用户的设置页面时仍然出现此错误。问题是数据库中没有这些字段的值。

这里是代码。

  userSettings: IUserSettings = {
    gender: null,
    drinks: null,
    smoking: null,
    ageRange: this.ageRange,
    distance: this.distance,
    notifications: true,
    dateOfBirth: null
  };


  ngOnInit() {
    console.log('settings', this.userSettings)
    this.afAuth.authState.subscribe(user => {
      this.getDataSvc.getUserFromFirebase(user.uid)
        .then((data) => {
          this.userSettings = data.data().userSettings;
        }).catch((error) => {
          console.log('errr', error);

        });
    });
  }

      <ion-button expand="block" color="success" style="margin-bottom: 20px;">
        <ion-icon size="large" name="transgender-outline" padding-left="20px"></ion-icon>
        <ion-select id="gender" name="gender" placeholder="Gender" required #genderField="ngModel"
          [(ngModel)]="userSettings.gender" [class.field-error]="form.submitted && genderField.invalid">
          <ion-select-option>Female</ion-select-option>
          <ion-select-option>Male</ion-select-option>
          <ion-select-option>Other</ion-select-option>
          <ion-select-option>No Preference</ion-select-option>
        </ion-select>
      </ion-button>
      <div [hidden]="genderField.valid || genderField.untouched" class="alert alert-danger">
        Must select an option
      </div>

我最初以为我可以向[[ngModel）] =“ userSettings？.gender”添加一个空检查，但这不起作用。

当我进入设置页面时，它一直显示相同的错误：

ProfileSettingsPage.html:16 ERROR TypeError: Cannot read property 'gender' of undefined
    at Object.eval [as updateDirectives] (ProfileSettingsPage.html:17)
    at Object.debugUpdateDirectives [as updateDirectives] (core.js:45259)
    at checkAndUpdateView (core.js:44271)
    at callViewAction (core.js:44637)
    at execComponentViewsAction (core.js:44565)
    at checkAndUpdateView (core.js:44278)
    at callViewAction (core.js:44637)
    at execEmbeddedViewsAction (core.js:44594)
    at checkAndUpdateView (core.js:44272)
    at callViewAction (core.js:44637)

2
投票

您看到的错误是因为甚至在您具有userSettings值之前就已加载DOM元素。如@robbieAreBest所述。您需要将父块包装在* ngIf中，以检查userSettings。

您的选择离子不知道加载时的用户设置。

    <ion-button *ngIf="userSettings" expand="block" color="success" style="margin-bottom: 20px;">
            <ion-icon size="large" name="transgender-outline" padding-left="20px"></ion-icon>
            <ion-select id="gender" name="gender" placeholder="Gender" required #genderField="ngModel"
              [(ngModel)]="userSettings.gender" [class.field-error]="form.submitted && genderField.invalid">
              <ion-select-option>Female</ion-select-option>
              <ion-select-option>Male</ion-select-option>
              <ion-select-option>Other</ion-select-option>
              <ion-select-option>No Preference</ion-select-option>
            </ion-select>
          </ion-button>
<span *ngIf="!userSettings">Loading data...</span> // this is optional

0
投票

所以不是使用对象，而是使用原始类型作为ngModel来解决此问题。

 gender: string;
  drinks: string;
  smoking: string;
  notifications: boolean = true;

  userSettings: IUserSettings = {
    gender: null,
    drinks: null,
    smoking: null,
    ageRange: this.ageRange,
    distance: this.distance,
    notifications: true,
    dateOfBirth: null
  };

  validations_form: FormGroup;
  errorMessage: string = '';

  constructor(private router: Router,
    private dataSvc: DataService,
    private afAuth: AngularFireAuth,
    private getDataSvc: GetDataService,
  ) { }

  ngOnInit() {
    console.log('settings', this.userSettings)
    this.afAuth.authState.subscribe(user => {
      this.getDataSvc.getUserFromFirebase(user.uid)
        .then((data) => {
          this.gender = data.data().userSettings.gender,
            this.drinks = data.data().userSettings.drinks,
            this.ageRange = data.data().userSettings.ageRange,
            this.distance = data.data().userSettings.distance,
            this.notifications = data.data().userSettings.notifications
        }).catch((error) => {
          console.log('errr', error);
        });
    });
  }

  goToProfilePage() {
    this.router.navigateByUrl('tabs/profile');
  }

  savePersonalInfo(form) {
    console.log(form.valid);
    if (form.valid) {
      this.userSettings = {
        gender: form.value.gender,
        drinks: form.value.drinks,
        smoking: form.value.smoking,
        ageRange: this.ageRange,
        distance: this.distance,
        notifications: this.notifications,
        dateOfBirth: null
      };
      this.dataSvc.addUserSettings(this.userSettings).then(() => {
        this.goToProfilePage();
      }
      )
    }

    <ion-card >
      <ion-button  expand="block" color="success" style="margin-bottom: 20px;">
        <ion-icon size="large" name="transgender-outline" padding-left="20px"></ion-icon>
        <ion-select id="gender" name="gender" placeholder="Gender" required #genderField="ngModel"
          [(ngModel)]="gender" [class.field-error]="form.submitted && genderField.invalid">
          <ion-select-option>Female</ion-select-option>
          <ion-select-option>Male</ion-select-option>
          <ion-select-option>Other</ion-select-option>
          <ion-select-option>No Preference</ion-select-option>
        </ion-select>
      </ion-button >
      <div [hidden]="genderField.valid || genderField.untouched" class="alert alert-danger">
        Must select an option
      </div>

[当我在HTML ngModel中使用基本类型时，它可以工作

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