角度2嵌套模型驱动表单的自定义验证器

Question

我有一个反应形式，表格使用ngFor嵌套。我需要根据银行名称验证银行帐号，每个表单的银行帐号可能不同。我遇到的问题似乎只验证一个表单实例的银行帐号。

自定义验证器

  ValidateBankAccountNumber(control: AbstractControl) {
    if (this.ddGroup.controls) {
        const bankName = this.ddGroup.controls['bank'].value;
        if (bankName === "") {
          return { noBank: true };
        }
        const bankAcNo: string = control.value;
        if (bankName === 'MBC-01' && bankAcNo.length !== 12) {
          return { wrongMCBAcc: true };
        } 
    }
    return null;
  }

根据付款方式，验证人将按以下方式更新

modeControlChanges$.subscribe(mode => {
  if (mode === 'DD') {
    //loop through each control of the formgroup and set validators accordingly
    Object.keys(formDdGroup.controls).forEach(key => {

      if (key === "bankNo" && modeTypeControl.value === "AD") {
        formDdGroup.controls[key].setValidators([Validators.required, this.ValidateBankAccountNumber.bind(this)]);
      }

      formDdGroup.controls[key].updateValueAndValidity();
    });
  }
})