如果类在模板驱动表单 Angular 4 中无效，为什么它不应用于输入元素？

Question

我为我的登录页面使用了模板驱动的表单。如果输入元素无效或有任何错误，我想要一个红色边框，但是当输入为空白或无效时，borderRed类并未添加在输入元素上。

<form (ngSubmit)="f.form.valid && signin()" #f="ngForm" class="m-login__form m-form" action="">
  <ng-template #alertSignin></ng-template>
  <div class="form-group form-md-line-input form-md-floating-label">
    <label>
      Email <span class="text-danger">*</span>
    </label>
    <input [class.borderRed]="email.invalid" class="form-control m-input" type="text" required="required" name="email" [(ngModel)]="model.email" #email="ngModel" autocomplete="off">
  </div>
  <div class="form-group form-md-line-input form-md-floating-label">
    <label [pTooltip]="attachementTooltipmsg" tooltipPosition="top" for="form_control_1">
      Password <span class="text-danger">*</span>
    </label>
    <input [class.borderRed]="password.invalid" class="form-control m-input" required="" name="password" type="password" [(ngModel)]="model.password" #password="ngModel">
  </div>
  <div class="m-login__form-action">
    <button [disabled]="loading" [ngClass]="{'m-loader m-loader--right m-loader--light': loading}" id="m_login_signin_submit" class="btn btn-focus m-btn m-btn--pill m-btn--custom m-btn--air">
      Sign In
    </button>
  </div>
</form>

Answer 1

使用此

   <input [class.borderRed]="email.touched && !email.valid" class="form-control m-input" type="email" pattern="[a-z0-9._%+-]+@[a-z0-9.-]+.[a-z]{2,3}$" required name="email" [(ngModel)]="model.email" #email="ngModel" autocomplete="off">

查看Stackbiltz

编辑代码

Answer 2

Angular在输入是否有效时添加一些CSS类。您可以覆盖CSS以使其看起来按照自己的意愿。使用这种方法，您不必在每个输入上进行[class.borderRed]=...。https://angular.io/guide/forms

.ng-valid[required], .ng-valid.required  {
  border: 1px solid green;
}
.ng-invalid:not(form)  {
  border: 1px solid red;
}

Answer 3

这应该有效

<input [ngClass]="{'borderRed':email.invalid}" class="form-control m-input" type="text" required="required" name="email" [(ngModel)]="model.email" #email="ngModel" autocomplete="off">

Answer 4

用于电子邮件验证的添加email指令 <input type="email" name="email" ngModel email>

或者您可以使用pattern属性，示例：

<div class="form-group">
              <label for="inputEmail">Email</label>
              <input type="text"
                [ngModel] = "user.email" name="email"
                #email="ngModel" id="inputEmail"
                placeholder="Email"
                pattern="[a-z0-9._%+-]+@[a-z0-9.-]+.[a-z]{2,3}$"
                required>
            </div>
<!-- This is the error section -->
<div *ngIf="email.invalid && (email.dirty || email.touched)"
    class="alert alert-danger">
    <div *ngIf = "email.errors?.required">
        Email field can't be blank
    </div>
    <div *ngIf = "email.errors?.pattern && email.touched">
        The email id doesn't seem right
    </div>
 </div>

也最好仅通过添加required来标记所需的字段。对于密码输入，您可以使用此 minlength ="8"这样的验证器。

通常，您必须指定验证规则。在反应性形式中，您将在组件类中指定：

this.myForm = this.f.group({ name: ['', Validators.required ], });

Answer 5

您可以执行此操作。这对我有用： -

<div class="form-group" [class.has-error]="fullnameControl.invalid && (fullnameControl.dirty || fullnameControl.touched)" 
        [class.has-success]="fullnameControl.valid">
            <label class="control-label">Full Name Field </label>
            <input 
                type="text" 
                required
                class="form-control" 
                name="fullname" 
                id="fullname" [(ngModel)]="fullname"
                #fullnameControl="ngModel"
            />
            <span class="help-block" 
               *ngIf="fullnameControl.invalid && (fullnameControl.dirty 
              || fullnameControl.touched)">Full Name is required. </span>
        </div>

Answer 6

使用ngclass动态添加不同的类。示例：

     <input class="form-control" id="firstName" name="firstName" type="text" placeholder="First Name" formControlName="firstName" [ngClass]="{
            'has-success': firstName.valid,
            'has-danger': (firstName.invalid && firstName.dirty) || (!isFormSubmitted && firstName.invalid)}">

如果 firstName 无效而肮脏(用户实际触摸了此字段(，然后添加 hast-danger class。>是有效的，然后添加 has-success class。
注意： firstName 是一个form-control