Angular7 Formarray不显示从服务/api收到的所有记录

我试图将从webapi接收到的对象修补为角度反应形式。表单也有一个formarray。但是，尽管有超过3条或更多的记录，但只有2条记录被修补到反应表单的格式阵列中

//initialization of form
    this.noseriesForm = this.fb.group({
      id: [null],
      description: ['', Validators.required],
      code: [ '', Validators.compose([Validators.maxLength(10), Validators.required])],
      noSeriesList: this.fb.array([
         this.initLine(), this.initLine()
      ])
    });

//patching the object received from service to form
 this.route.params.subscribe(routeParam => {
      if (routeParam.id) {
        this.noseriesService.get(routeParam.id)
        .subscribe((data: NoSeries) => {
          this.isCreateMode = false;
          this.noseries = data;
          this.noseriesForm.patchValue(this.noseries);
          console.log(this.noseries, 'data from api');
          console.log(this.noseriesForm.value,'formvalue');
        });
      }

    });

//initialise formArray
  initLine(): FormGroup {
    return this.fb.group({
      id: [null],
      startingNoSeries: ['', Validators.required],
      endingNoSeries: '',
      lastUsedSeries: '',
      effectiveDate: [null],
      endingDate: [null],
      noSeriesId: [null]
    });
  }

我有两个实体noseries和noseriesList，其中一个noseries有零个或多个noseriesList。因此，在从webapi获得noseries之后，我想将noseries的属性和导航列表“NoseriesList”修补为反应形式。 其余属性正在正确修补，但只有2条导航列表记录“NosriesList”正在修补到嵌套在反应表单中的formArray

//initialization of form
    this.noseriesForm = this.fb.group({
      id: [null],
      description: ['', Validators.required],
      code: [ '', Validators.compose([Validators.maxLength(10), Validators.required])],
      noSeriesList: this.fb.array([
         this.initLine(), this.initLine()
      ])
    });

//patching the object received from service to form
 this.route.params.subscribe(routeParam => {
      if (routeParam.id) {
        this.noseriesService.get(routeParam.id)
        .subscribe((data: NoSeries) => {
          this.isCreateMode = false;
          this.noseries = data;
          this.noseriesForm.patchValue(this.noseries);
          console.log(this.noseries, 'data from api');
          console.log(this.noseriesForm.value,'formvalue');
        });
      }

    });

//initialise formArray
  initLine(): FormGroup {
    return this.fb.group({
      id: [null],
      startingNoSeries: ['', Validators.required],
      endingNoSeries: '',
      lastUsedSeries: '',
      effectiveDate: [null],
      endingDate: [null],
      noSeriesId: [null]
    });
  }

---

记录从服务接收的数据显示3条noseriesList记录，而记录formvalue仅显示2条noseriesList记录。

当您第一次初始化表单数组并添加两个空控件时。这就是为什么当您将值修补到formgroup时，只有这两个空控件被填充。在修补值之前，您应该在formarray中填入要修补的控件数

//将从服务接收的对象修补到表单
this.route.params.subscribe（routeParam=>{
if（routeParam.id）{
this.noseriesService.get（routeParam.id）.subscribe（（数据：NoSeries）=>{
this.isCreateMode=false；
this.noseries=数据；
const nsList=this.noseriesForm.get（“noSeriesList”）作为FormArray；
nsList.clear（）；
this.noseries.forEach（=>nsList.push（this.initLine（））；
this.noseriesForm.patchValue（this.noseries）；
log（this.noseries，“来自api的数据”）；
log（this.noseriesForm.value，'formvalue'）；
});
}
});