I am aware that Angular 2 currently lacks a way to easily reset a form to a pristine state. Poking around I have found a solution like the one below that resets the form fields.
It has been suggested that I need to drop the control group and create a new one to rebuild the form as pristine. I am having difficulty figuring out the best way to do this. I know I need to wrap the form building within a function but I am running into errors when doing that within the constructor.
What would be the best way to rebuild the control group to completely reset the form?
class App {
name: Control;
username: Control;
email: Control;
form: ControlGroup;
constructor(private builder: FormBuilder) {
this.name = new Control('', Validators.required);
this.email = new Control('', Validators.required);
this.username = new Control('', Validators.required);
this.form = builder.group({
name: this.name,
email: this.email,
username: this.username
});
}
onSubmit(value: any): void {
// code that happens when form is submitted
// then reset the form
this.reset();
}
reset() {
for (let name in this.form.controls) {
this.form.controls[name].updateValue('');
this.form.controls[name].setErrors(null);
}
}
}
>= RC.6
Support resetting forms and maintain a submitted
state.
console.log(this.form.submitted);
this.form.reset()
or
this.form = new FormGroup()...;
importat update
To set the Form controls to a state when the form is created, like validators, some additional measurements are necessary
In the view part of the form (html) add an *ngIf
to show or hide the form
<form *ngIf="showForm"
In the component side of the form (*.ts) do this
showForm:boolean = true;
onSubmit(value:any):void {
this.showForm = false;
setTimeout(() => {
this.reset()
this.showForm = true;
});
}
Here is a more detailed example:
export class CreateParkingComponent implements OnInit {
createParkingForm: FormGroup ;
showForm = true ;
constructor(
private formBuilder: FormBuilder,
private parkingService: ParkingService,
private snackBar: MatSnackBar) {
this.prepareForm() ;
}
prepareForm() {
this.createParkingForm = this.formBuilder.group({
'name': ['', Validators.compose([Validators.required, Validators.minLength(5)])],
'company': ['', Validators.minLength(5)],
'city': ['', Validators.required],
'address': ['', Validators.compose([Validators.required, Validators.minLength(10)])],
'latitude': [''],
'longitude': [''],
'phone': ['', Validators.compose([Validators.required, Validators.minLength(7)])],
'pictureUrl': [''],
// process the 3 input values of the maxCapacity'
'pricingText': ['', Validators.compose([Validators.required, Validators.minLength(10)])],
'ceilingType': ['', Validators.required],
});
}
ngOnInit() {
}
resetForm(form: FormGroup) {
this.prepareForm();
}
createParkingSubmit() {
// Hide the form while the submit is done
this.showForm = false ;
// In this case call the backend and react to the success or fail answer
this.parkingService.create(p).subscribe(
response => {
console.log(response);
this.snackBar.open('Parqueadero creado', 'X', {duration: 3000});
setTimeout(() => {
//reset the form and show it again
this.prepareForm();
this.showForm = true;
});
}
, error => {
console.log(error);
this.showForm = true ;
this.snackBar.open('ERROR: al crear Parqueadero:' + error.message);
}
);
}
}
original <= RC.5 Just move the code that creates the form to a method and call it again after you handled submit:
@Component({
selector: 'form-component',
template: `
<form (ngSubmit)="onSubmit($event)" [ngFormModel]="form">
<input type="test" ngControl="name">
<input type="test" ngControl="email">
<input type="test" ngControl="username">
<button type="submit">submit</button>
</form>
<div>name: {{name.value}}</div>
<div>email: {{email.value}}</div>
<div>username: {{username.value}}</div>
`
})
class FormComponent {
name:Control;
username:Control;
email:Control;
form:ControlGroup;
constructor(private builder:FormBuilder) {
this.createForm();
}
createForm() {
this.name = new Control('', Validators.required);
this.email = new Control('', Validators.required);
this.username = new Control('', Validators.required);
this.form = this.builder.group({
name: this.name,
email: this.email,
username: this.username
});
}
onSubmit(value:any):void {
// code that happens when form is submitted
// then reset the form
this.reset();
}
reset() {
this.createForm();
}
}