Angular 4 : ngNativeValidate is not allowed in Form - html

Question

I'm using Angular 4 to build a form and required attribute is not working. I tried adding <form ngNativeValidate>...</form> as suggested by many answers but i got :
Attribute ngNativeValidate is not allowed here.
Here is my code :
<form #f="ngForm" (ngSubmit)="submit()" ngNativeValidate>
<div class="form-group input-group">
<span class="input-group-addon"><i class="glyphicon glyphicon-user"></i></span>
<input class="form-control" type="text" [(ngModel)] = "email" name='email' placeholder="Email" required/>
</div>
<div class="form-group">
<button type="submit" class="btn btn-def btn-block">Submit</button>
</div>
</form>

Answer 1

try to replace this : <input class="form-control" type="text" [(ngModel)] = "email" name='email' placeholder="Email" required/>
with this : <input class="form-control" type="text" ngModel #email="ngModel" name='email' placeholder="Email" required/>
so all your code should look like this :
<form #f="ngForm" (ngSubmit)="submit()">
<div class="form-group input-group">
<span class="input-group-addon"><i class="glyphicon glyphicon-user"></i></span>
<input class="form-control" type="text" ngModel #email="ngModel" name='email' placeholder="Email" required/>
</div>
<div class="alert alert-danger" role="alert" *ngIf="!email.valid && email.touched" >
<span *ngIf="!email.valid"> This field is required</span>
</div>
<div class="form-group">
<button type="submit" class="btn btn-def btn-block">Submit</button>
</div>
</form>
Also remove the unnecessary ngNativeValidate and it should work now.