Question

我正在尝试通过以下代码实现双向绑定：

export interface User {
  name: string;
  subscribed: boolean;
}

export class UserEditComponent implements OnInit {
  modifiedUser: User;
  userForm: FormGroup;

  ngOnInit() {
    this.userForm = this.fb.group({
      name: ['', Validators.required],
      subscribed: false
    });

    this.route.paramMap.switchMap((params: ParamMap) => {
      return this.userService.getUser(params.get('id'));
    }).subscribe((user) => {
      this.modifiedUser = user;
      this.userForm.setValue({
        name: this.modifiedUser.name,
        subscribed: this.modifiedUser.subscribed
      });
    });

    this.userForm.valueChanges.subscribe((data) => {
      this.modifiedUser.subscribed = data.subscribed;
    });
  }
}

<form [formGroup]="userForm">
  <textarea class="form-control" formControlName="name">{{modifiedUser.name}}</textarea>
  <input type="checkbox" class="custom-control-input" formControlName="subscribed">
</form>

但是，一旦表单出现，我总是在控制台中收到错误TypeError: Cannot assign to read only property 'subscribed' of object '[object Object]'。知道为什么吗？

Answer 1

.thumb-wrapper结果证实确实是只读的。我只需要制作一份this.modifiedUser对象的深层副本来解决问题。

Answer 2

检查您的模块设置，您是否有类似的东西？

StoreModule.forRoot(reducers, {
        metaReducers,
        runtimeChecks: {
            strictStateImmutability: true,
            strictActionImmutability: false,
            strictStateSerializability: true,
            strictActionSerializability: true
        }
    })

我禁用了strictActionImmutability属性，另一种选择是使用ng serve --prod标志运行--prod，如果仅运行ng serve，则需要将{{ 1}}属性中的strictActionImmutability对象

Reactive Forms双向绑定错误：无法分配给只读属性

2 个答案: