Angular 形成数组，第一个索引始终为空

Question

请协助，我正在尝试使用 angular 表单数组查看从组件到视图的数据。以下解决方案：。帮助了我，但现在我遇到了一个问题，即表单数组的第一个索引始终为空，并且我收到以下错误：

ERROR Error: Cannot find control with path: '[object Object] -> 0'
at _throwError (forms.js:2432)
at setUpFormContainer (forms.js:2405)
at FormGroupDirective.addFormGroup (forms.js:6691)
at FormGroupName.AbstractFormGroupDirective.ngOnInit (forms.js:2568) 
...

Cannot read property 'controls' of undefined
at Object.eval [as updateDirectives] 
...

在我的 ngOnInit 中我只有以下内容：

this.SectionForm= this.formBuilder.group({
  sectionData: this.formBuilder.array([this.buildDevelopmentSector()])
});

this.activatedRoute.params.subscribe(res =>
  // get data and push the data to a formArray called sectionDataArray
  this.GetDataFromApi(res.requestId)
);

视图包含以下部分：

  <div [formGroup] ="SectionForm">
    <div [formArrayName]="sectionDataArray">
      <div *ngFor="let section of sectionDataArray.controls ; let i = index" [formGroupName]="i">
          ...
          ...
          ...
        </div>

查看日志，我看到以下内容：

  0:
     amount:""
     percentage:""
     name:""
     quantity:""
     __proto__:Object 

  1:
     amount:1200000
     percentage:23
     name: "Repo"
     quantity:20000
     __proto__:Object

  length:2
     __proto__:Array(0)

Answer 1

您的支持对象有

sectionData: this.formBuilder.array([this.buildDevelopmentSector()])

所以它是 sectionData 但你在这里指的是 sectionDataArray

<div [formArrayName]="sectionDataArray">

改为sectionData

Angular 形成数组，第一个索引始终为空

Angular Form Array, first Index always null

angular

angular-reactive-forms

angular5