文本区域验证使用 *ngIf 使用 angular 4

Question

<label for="description">description <span class="required-field">*</span></label>
<textarea rows="5" cols="20" class="form-control" id="description" name="description" required minlength="1" maxlength="2">
</textarea>

How to check the validation based on touched event and required field

Answer 1

ngForm is a solution.

You can try this:

.html

<form (submit)="onSubmit() #f="ngForm">
  <label for="description">description <span class="required-field">*</span></label>

  <textarea
  id="description"
  name="description"
  rows="5"
  cols="20"
  class="form-control"
  minlength="1"
  maxlength="2"
  required
  #mytext="ngModel"
  ngModel>
  </textarea>

  <button type="submit" class="btn btn-outline-dark" [disabled]="f.invalid | mytext.touched">Ok</button>
</form>

.ts

onSubmit() {
  console.log('it is working');
}

Don't forget to import FormsModule in your app.module.ts

import { FormsModule } from '@angular/forms';
…


import: [
  …
  FormsModule
]

For more details, check this: https://angular.io/guide/forms