角度6密码验证不起作用

Question

i am trying to validate below field. but error messages did not appear. please check my code. thanks

     <div class="form-group">
            <input type="password" minlength="10" required [ngClass]="{'is-invalid':lgform.submitted && password.invalid}" name="password" id="inputPassword" #password="ngModel" class="form-control" placeholder="Password"  [(ngModel)]="model.password">
            <div *ngIf="lgform.submitted && password.invalid" class="invalid-feedback">
             <div *ngIf="password.errors['required']">Password is required</div>  
             <div *ngIf="password.errors['minlength']">minlength 10</div>  
          </div>

        </div>

Answer 1

use <form #lgform="ngForm"> in your code.

Stackblitz Demo

component.html

<form #lgform="ngForm">
    <div class="form-group">
        <input type="password" minlength="10" required [ngClass]="{'is-invalid':lgform.submitted && password.invalid}"
            name="password" id="inputPassword" #password="ngModel" class="form-control" placeholder="Password"
            [(ngModel)]="model.password">

        <div *ngIf="lgform.submitted && password.invalid" class="invalid-feedback">
            <div *ngIf="password.errors['required']">Password is required</div>
            <div *ngIf="password.errors['minlength']">minlength 10</div>
        </div>

    </div>
    <button type="submit" class="btn btn-success">Submit</button>
</form>

Answer 2

Take a look at my library Easy Angular.

https://github.com/adriandavidbrand/ezng

And have a look at a StackBlitz demo on how easy form validation with it is.

https://stackblitz.com/edit/angular-8brst8?file=src%2Fapp%2Fapp.component.html

None of the boilerplate code is needed.

<ez-password minlength="10" required>Password</ez-password>

Is all you need.