如何在angular2中获取FormControl的值

How to get the value of a FormControl in angular2

我有以下表单和一个包含 FormGroups 的 FormArray

 <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 值来自通过 API 填充的数组 在回调中我设置了值:

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([]),
});

}

我觉得这行代码很奇怪

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?

试试这个:

screenForm.get('url').value

如果这不起作用,我将不得不查看您的整个表单生成器以进一步提供帮助。

你可以尝试从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 Example