NGFOR内的反应形式

我有一个NGFOR,里面有一个反应形式。这是代码:

<div class="element-list">
        <form [formGroup]="formGroup" class="single-item" *ngFor="let p of points; let i = index">
            <span>Lat: </span> <input formControlName="lat" type="text" value="{{p.lat}}">
            <span>Lon: </span> <input formControlName="lon" type="text" value="{{p.lon}}">
            <a (click)="updateData(i)">Submit</a>
        </form>
    </div>

这是TS侧

export class MapInfoBarComponent implements OnInit, OnDestroy
{
  points: MapDetailModel[] = [];
  isAlive = true;
  formGroup: FormGroup;


  constructor(
    private mapService: MapService,
    private fb: FormBuilder
    ){}

  ngOnInit() {

    this.mapService.pointsChanged
    .takeWhile(() => this.isAlive)
    .subscribe( evt => {
      if(!!evt){
        this.points = evt;
      }
    });

    this.formGroup = this.fb.group({
      lat: new FormControl(),
      lon: new FormControl()
    });
  }


  ngOnDestroy(): void {
    this.isAlive = false;
  }

  updateData(id: number){
    console.log(id + " > " + this.formGroup.value);
  }
}

每当我点击 a 我从中得到了什么 this.formGroup.value 只是空值和空值。

问题

我的问题是,每当我单击一个按钮时,如何“知道”我指的是哪个窗体组? this.points 有时会改变,从另一个组件推送新元素。

例如,我想更新第三个元素,并在 console.log 更新的值。

感谢您的帮助。谢谢。

我是如何解决这个问题的

感谢@ak.leimrey通过下面的链接。

我是这样解决的:

TS文件:

export class MapInfoBarComponent implements OnInit, OnDestroy
{
  points: MapDetailModel[] = [];
  isAlive = true;
  survey: FormGroup;
  items = false;

  constructor(
    private mapService: MapService,
    private fb: FormBuilder
    ){}

  ngOnInit() {



    this.mapService.pointsChanged
    .takeWhile(() => this.isAlive)
    .subscribe( evt => {
      if(!!evt){
        this.points = evt;

        if(!this.items){
          this.survey = this.fb.group({
            sections: this.fb.array([
              this.initSection(0),
            ]),
          });
          this.items = true;
        } else {
          this.addSection(this.points.length - 1);
        }
      }
    });
  }


  initSection(idx: number) {
    return this.fb.group({
      lat: [this.points[idx].lat],
      lon: [this.points[idx].lon],
    })
  }

  addSection(idx: number) {
    const control = <FormArray>this.survey.get('sections');
    control.push(this.initSection(idx));
  }

  getSections(form) {
    //console.log(form.get('sections').controls);
    return form.controls.sections.controls;
  }

  updateData(index: number){
    const values = this.survey.value.sections[index] as MapDetailModel;
    this.mapService.setChangePoint(values);
  }

  ngOnDestroy(): void {
    this.isAlive = false;
  }
}

HTML文件:

<div class="main-wrapper">
    <div class="map-info-bar">
        <div class="blocco-info">
            {{lang.phrase('Coord')}}: {{lang.phrase('Lat')}} {{currentLatitude}} {{lang.phrase('Lon')}} {{currentLongitude}}
        </div>
        <div class="blocco-info">
            <dx-select-box [items]="zoomLevels" [value]="scale" (onValueChanged)="onScaleChange($event.value)">
            </dx-select-box>
        </div>
    </div>

    <div class="element-list">
        <form [formGroup]="survey" novalidate (ngSubmit)="onSubmit(survey)" *ngIf="items">
            <div formArrayName="sections">
                <div class="single-item" *ngFor="let section of getSections(survey); let i = index">
                    <div  [formGroupName]="i">
                        <input type="text" formControlName="lat" class="frm-txt">
                        <input type="text" formControlName="lon" class="frm-txt">
                        <a (click)="updateData(i)">Update data</a>
                    </div>
                </div>
            </div>
        </form>
    </div>
</div>

班级:

export class MapDetailModel{
    lat: number;
    lon: number;
    alt: number;
    long?: number;
}