Narendra CM Narendra CM - 2 months ago 14
Javascript Question

Angular2 Reactive forms - Set default value for form fields with dropdown

How can I set the default value for all forms fields in angular 2 reactive forms.

Here is the plnkr to reproduce the issue

Below code doesnot update dropdown values as it has object associated with it.

Note: Here I need to set default value for all form fields with response received from Backend API.

Component.html

<form [formGroup]="myForm" novalidate (ngSubmit)="save(myForm.value, myForm.valid)">
<div class="form-group">
<label>Country:</label>
<select formControlName="country">
<option *ngFor="let country of masterCountries" [ngValue]="country">{{country.countryName}}</option>
</select>
</div>

<div class="form-group">
<label for="">Name</label>
<input type="text" class="form-control" formControlName="name">
<small [hidden]="myForm.controls.name.valid || (myForm.controls.name.pristine && !submitted)" class="text-danger">
Name is required (minimum 5 characters).
</small>
<!--<pre class="margin-20">{{ myForm.controls.name.errors | json }}</pre>-->
</div>
<button type="submit" class="btn btn-default">Submit</button>
<div class="margin-20">
<div>myForm details:-</div>
<pre>Is myForm valid?: <br>{{myForm.valid | json}}</pre>
<pre>Is myForm submitted?: <br>{{submitted | json}}</pre>
<pre>myForm value: <br>{{myForm.value | json}}</pre>
</div>




Component.ts

export class AppComponent implements OnInit {
public myForm: FormGroup;
public masterCountries: any[] = [{"countryCode":"AF","countryName":"Afghanistan"},{"countryCode":"AL","countryName":"Albania"},{"countryCode":"DZ","countryName":"Algeria"},{"countryCode":"AS","countryName":"American Samoa"},{"countryCode":"AD","countryName":"Andorra"}];

// Sample response received from backend api
public CountryResponse = {country: {"countryCode":"AF","countryName":"Afghanistan"}, name: 'test123'};
constructor(private _fb: FormBuilder) { }

ngOnInit() {

// the short way
this.myForm = this._fb.group({
country: [''],
name: ['', [<any>Validators.required, <any>Validators.minLength(5)]],
});


(<FormGroup>this.myForm)
.setValue(this.CountryResponse, {onlySelf: true});


}


save(model: User, isValid: boolean) {
this.submitted = true;
console.log(model, isValid);
}
}


Let me know if there is any other way to set the whole form.

Answer Source

Just change this:

 (<FormGroup>this.myForm)
            .setValue(this.CountryResponse, {onlySelf: true});

Into this:

const selectedCountry = this.masterCountries.find(country => country.countryCode === this.CountryResponse.country.countryCode)
this.CountryResponse.country = selectedCountry;
(<FormGroup>this.myForm)
            .setValue(this.CountryResponse, {onlySelf: true});

As said before you need to pass the exact same reference of the object