如何显示反应式表单验证错误消息

Question

大家好，

我正在努力为名称输入制作验证器，我刚刚回复了 angular wiki 中的代码，但仍然无法正常工作。

你能帮我找出问题吗？

谢谢指教。

我的HTML代码：

  <form [formGroup]="formAlta" (ngSubmit)="addRepresentacio()">
            <div class="form-group">
              <label for="namePro">Nom</label>
              <input id="namePro" class="form-control" formControlName="namePro" placeholder="Nom del professional" required>
              <div *ngIf="namePro.invalid && (namePro.dirty || namePro.touched)" class="alert alert-danger form-danger" role="alert">

        <div *ngIf="namePro.errors.required">
            El Nom del professional es obligatori
        </div>
    </div></form>

还有我的 TS 组件

 formAlta: FormGroup;
 ngOnInit() {
    this.formAlta = new FormGroup({
      idPro: new FormControl(),
      documentTypePro: new FormControl(),
      namePro: new FormControl('',[Validators.required]),
      rProfessional: new FormControl(this.tipusPro),
      firstSurnamePro: new FormControl(),
      secondSurnamePro: new FormControl(),
      businessNamePro: new FormControl(),
      idCli: new FormControl(),
      documentTypeCli: new FormControl(),
      nameCli: new FormControl('',Validators.required),
      rClient: new FormControl(this.tipusCli),
      firstSurnameCli: new FormControl(),
      secondSurnameCli: new FormControl(),
      businessNameCli: new FormControl(),
      idPermis: new FormArray([]),
      dateFiPermis: new FormArray([])
    });
  }

Answer 1

您应该在 component.ts 中创建一个 getter 方法，如下所示，以获取模板中的表单控件

get formAltaControls(): any {
   return this.formAlta['controls'];
}

在你的componen.html

<div *ngIf="formAltaControls.namePro.invalid && (formAltaControls.namePro.dirty || formAltaControls.namePro.touched)" class="alert alert-danger form-danger" role="alert">

    <div *ngIf="formAltaControls.namePro.errors.required">
        El Nom del professional es obligatori
    </div>

Answer 2

我认为你必须用类似的东西来改变你的代码

  <form [formGroup]="formAlta" (ngSubmit)="addRepresentacio()">
        <div class="form-group">
          <label for="namePro">Nom</label>
          <input id="namePro" class="form-control" formControlName="namePro" placeholder="Nom del professional" required>
          <div *ngIf="formAlta.controls['namePro'].invalid && (formAlta.controls['namePro'].dirty || formAlta.controls['namePro'].touched)" class="alert alert-danger form-danger" role="alert">

    <div *ngIf="formAlta.controls['namePro'].errors.required">
        El Nom del professional es obligatori
    </div>
</div></form>

Answer 3

如果您输入空的，您的输入字段可能如下所示

在html中你可以像

那样使用波纹管

<form class="brown-text" [formGroup]="basicInfoForm">
           <input type="text"  class="form-control"  formControlName="firstName" [ngClass]="{ 'is-invalid': (basicInfoForm.controls.firstName.errors) || (!basicInfoForm.controls.firstName.pristine && basicInfoForm.controls.firstName.invalid) }">
               
                <!-- Validation messages -->
              <div class="invalid-feedback"  *ngIf="(basicInfoForm.controls.firstName.errors) || (!basicInfoForm.controls.firstName.pristine && basicInfoForm.controls.firstName.invalid)">
              <div *ngIf="basicInfoForm.controls.firstName.errors">Name is required</div>
              <div *ngIf="basicInfoForm.controls.firstName.errors">Only Alphabets with space  between 2 to  20   characters</div>
            </div>
   <form>

在 .ts 文件中你可以像下面这样使用波纹管

  this.basicInfoForm = this.formBuilder.group({
      firstName: new FormControl("Enter First Name", [Validators.required, Validators.pattern(this.PAT_NAME)])  

  });

如何显示反应式表单验证错误消息

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