Angular 2自定义验证器,用于检查何时需要两个字段之一

Question

我正在尝试实现自定义验证器功能来检查是否输入了电话号码(家庭电话和移动电话).我想在两个字段上显示错误消息,当它们被触摸并且没有有效值时,由于某种原因我的代码没有按预期工作.请帮帮我这篇文章.-谢谢!这是stackblitz链接https://stackblitz.com/edit/angular-ve5ctu

createFormGroup() {
   this.myForm = this.fb.group({
     mobile : new FormControl('', [this.atLeastOnePhoneRequired]),
     homePhone : new FormControl('', [this.atLeastOnePhoneRequired])
   });
}

atLeastOnePhoneRequired(control : AbstractControl) : {[s:string ]: boolean} {
  const group = control.parent;
  if (group) {
    if(group.controls['mobile'].value || group.controls['homePhone'].value) {
      return;
    }
  }
  let errorObj = {'error': false};
  return errorObj;
}

Answer 1

不是在每个formControl上标记验证器,而是为电话号码创建一个嵌套组,并将验证器应用于该组.在这个示例中,我将在整个表单上应用验证器.

同样在应用验证器时,我们需要null在字段有效时返回.

此外,由于您使用的是Angular材质,我们需要添加一个ErrorStateMatcher才能显示mat-errors.mat-errors仅在验证程序设置为表单控件而不是表单组时显示.

您的代码应如下所示:

createFormGroup() {
  this.myForm = this.fb.group({
    mobile : new FormControl(''),
    homePhone : new FormControl('')
      // our custom validator
  }, { validator: this.atLeastOnePhoneRequired});
}

atLeastOnePhoneRequired(group : FormGroup) : {[s:string ]: boolean} {
  if (group) {
    if(group.controls['mobile'].value || group.controls['homePhone'].value) {
      return null;
    }
  }
  return {'error': true};
}

错误状态匹配器:

export class MyErrorStateMatcher implements ErrorStateMatcher {
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    const controlTouched = !!(control && (control.dirty || control.touched));
    const controlInvalid = !!(control && control.invalid);
    const parentInvalid = !!(control && control.parent && control.parent.invalid && (control.parent.dirty || control.parent.touched));

    return (controlTouched && (controlInvalid || parentInvalid));
  }
}

你在组件中标记的:

matcher = new MyErrorStateMatcher();

然后在两个输入字段上将其标记为模板.还要注意*ngIf查看验证消息的方式:

<mat-form-field>
  <input matInput placeholder="Mobile" formControlName="mobile" [errorStateMatcher]="matcher">
  <mat-error *ngIf="myForm.hasError('error')">
    "Enter either phone number"
  </mat-error>
</mat-form-field>
<mat-form-field>
  <input matInput placeholder="Home Phone" formControlName="homePhone" [errorStateMatcher]="matcher">
  <mat-error *ngIf="myForm.hasError('error')">
    "Enter either phone number"
  </mat-error>
</mat-form-field>

StackBlitz