如何在angular2中获取FormControl的值

Question

我有一个包含FormGroups的FormArray的以下表单

 <form [formGroup]="screenForm" novalidate>

  <div formArrayName="iPhoneScreenshots" class="row">
    <div *ngIf="screenForm.controls.iPhoneScreenshots?.length > 0">
      {{screenForm.controls.iPhoneScreenshots?.length }}
      <div *ngFor="let url of screenForm.controls.iPhoneScreenshots.controls; let i=index">
        <div [formGroupName]="i">
          <input class="form-control" formControlName="url">
          <img src="{{app.screenshotUrls[i]}}" class="rounded img-fluid app-screen" style="height:200px"/>
        </div>
      </div>
    </div>
  </div>
</form>

url值来自一个数组,该数组在回调中通过API填充我设置的值:

private setScreenShots(app: ItunesApp): void {
if (app.hasOwnProperty('screenshotUrls')) {
  const screenShots = app.screenshotUrls.map(url => {
      return this.fb.group({
        url: [url, Validators.required]
      });
    }
  );
  const screenShotsArray = this.fb.array(screenShots);
  this.screenForm.setControl('iPhoneScreenshots', screenShotsArray);
 }
}

初始数组为空

 private createForm() {
   this.appSiteForm = this.fb.group({
  title: ['', Validators.required]
});

this.screenForm = this.fb.group({
  iPhoneScreenshots: this.fb.array([]),
});

}

这段代码对我来说很奇怪

img src="{{app.screenshotUrls[i]}}" 

我这样做是因为url.value()或url.get('value')会引发错误.

那么如何访问表单控件的值呢？

Answer 1

您可以尝试从url组获取控制权

<div *ngFor="let urlGroup of screenForm.controls.iPhoneScreenshots.controls; let i=index">
    <div [formGroupName]="i">
        <input class="form-control" formControlName="url">
        <img [src]="urlGroup.get('url').value" />
    </div>
</div>

Plunker示例

Answer 2

尝试这个：

screenForm.get('url').value

如果这不起作用，我将不得不查看您的整个表单构建器以提供进一步的帮助。