Angular 5 form validation (required) not working
Solution 1
You can use the errors
property, like so:
loginForm.controls['email'].errors
If there are no errors, it will return null, otherwise it will return an object like so:
{ required : true }
Then you simply need to create a function that will return a human readable error message, like so:
getErrorMessage(controlName, displayName) {
let result = "";
let errors = loginForm.controls[controlName].errors;
if (errors.required) {
result += (displayName + " is required.");
}
if (errors.whatever) {
result += "Whatever you like";
}
return result;
}
Solution 2
I have just spent a couple of hours trying to debug this problem in my project, the problem in my case turned out to be using:
<input type="checkbox" formControlName="testing" />
instead of:
<input type="checkbox" [formControl]="form.controls['testing']" />
In my case the FormControl "testing" is dynamically added using form.AddControl() - the second way of performing the name binding also binds the model to the input.
Hoping this can help someone with this issue!
Comments
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Wai Yan Hein almost 2 years
I am learning Angular 5 with TypeScript. I am completely new to it. I am now trying to construct a form and validating it. But it is not working properly.
This is my component:
@Component({ selector: 'app-login', templateUrl: './login.component.html', styleUrls: ['./login.component.scss'], animations: [routerTransition()] }) export class LoginComponent implements OnInit { loginForm: FormGroup; errors = []; constructor(private fb: FormBuilder, public router: Router, private globals: GlobalsService, private http: Http) { } ngOnInit() { this.loginForm = new FormGroup({ email: new FormControl("", Validators.required), password: new FormControl("") }); } onLoggedin(formData) { alert("Submit form"); } }
As you can see I am setting "required" validation attribute on the email field. This is my html.
<div class="login-page" [@routerTransition]> <div class="row justify-content-md-center"> <div class="col-md-4"> <img src="assets/images/logo.png" width="150px" class="user-avatar" /> <h1>Yo Cash Flow</h1> <div class="alert alert-danger" *ngFor="let error of errors"> <strong>{{ error.msg }}</strong> </div> <form [formGroup]="loginForm" role="form" (ngSubmit)="onLoggedin(loginForm.value)"> <div class="form-content"> <div class="form-group"> <input type="text" name="email" formControlName="email" class="form-control input-underline input-lg" placeholder="Email"> <div *ngIf="loginForm.controls['email'].errors.required" class="text-danger">Email is required</div> </div> </div> <button type="submit" class="btn rounded-btn"> Log in </button> <a class="btn rounded-btn" [routerLink]="['/signup']">Sign up</a> </form> </div> </div> </div>
As you can see I am trying to show the error individually. I mean for "required" attribute, I am retrieving the error message like this errors.required. But it is not working. But when I tried to use "valid" like below, it is working.
loginForm.controls['email'].invalid
But I want to retrieve the error individually because I want to show the different message for the different error. How can I fix this? Why it is not working when I use
loginForm.controls["email"].errors.required
? What is the correct way of showing the different message for the different validation rule?