How to clear form after submit in Angular 2?

2020-01-30 06:10发布

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问题:

I have some simple angular 2 component with template. How to clear form and all fields after submit?. I can't reload page. After set data with date.setValue('') field is stil touched.

import {Component} from 'angular2/core';
import {FORM_DIRECTIVES, FormBuilder, ControlGroup, Validators, Control} from 'angular2/common';

@Component({
    selector: 'loading-form',
    templateUrl: 'app/loadings/loading-form.component.html',
    directives: [FORM_DIRECTIVES]
})

export class LoadingFormComponent {
    private form:ControlGroup;
    private date:Control;
    private capacity:Control;

    constructor(private _loadingsService:LoadingsService, fb:FormBuilder) {
        this.date = new Control('', Validators.required);
        this.capacity = new Control('', Validators.required);
        this.form = fb.group({
            'date': this.date,
            'capacity': this.capacity
        });
    }

    onSubmit(value:any):void {
        //send some data to backend
    }
}

loading-form.component.html

<div class="card card-block">
    <h3 class="card-title">Loading form</h3>

    <form (ngSubmit)="onSubmit(form.value)" [ngFormModel]="form">
        <fieldset class="form-group" [class.has-danger]="!date.valid && date.touched">
            <label class="form-control-label" for="dateInput">Date</label>
            <input type="text" class="form-control form-control-danger form-control-success" id="dateInput"
                   min="0" placeholder="Enter loading date"
                   [ngFormControl]="form.controls['date']">
        </fieldset>
        <fieldset class="form-group" [class.has-danger]="!capacity.valid && capacity.touched">
            <label class="form-control-label" for="capacityInput">Capacity</label>
            <input type="number" class="form-control form-control-danger form-control-success" id="capacityInput"
                   placeholder="Enter capacity"
                   [ngFormControl]="form.controls['capacity']">
        </fieldset>
        <button type="submit" class="btn btn-primary" [disabled]="!form.valid">Submit
        </button>
    </form>
</div>

回答1:

See also https://angular.io/docs/ts/latest/guide/reactive-forms.html (section "reset the form flags")

>=RC.6

In RC.6 it should be supported to update the form model. Creating a new form group and assigning to myForm

[formGroup]="myForm"

will also be supported (https://github.com/angular/angular/pull/11051#issuecomment-243483654)

>=RC.5

form.reset();

In the new forms module (>= RC.5) NgForm has a reset() method and also supports a forms reset event. https://github.com/angular/angular/blob/6fd5bc075d70879c487c0188f6cd5b148e72a4dd/modules/%40angular/forms/src/directives/ng_form.ts#L179

<=RC.3

This will work:

onSubmit(value:any):void {
  //send some data to backend
  for(var name in form.controls) {
    (<Control>form.controls[name]).updateValue('');
    /*(<FormControl>form.controls[name]).updateValue('');*/ this should work in RC4 if `Control` is not working, working same in my case
    form.controls[name].setErrors(null);
  }
}

回答2:

As of Angular2 RC5, myFormGroup.reset() seems to do the trick.

回答3:

To reset your form after submitting, you can just simply invoke this.form.reset(). By calling reset() it will:

Mark the control and child controls as pristine.
Mark the control and child controls as untouched.
Set the value of control and child controls to custom value or null.
Update value/validity/errors of affected parties.

Please find this pull request for a detailed answer. FYI, this PR has already been merged to 2.0.0.

Hopefully this can be helpful and let me know if you have any other questions in regards to Angular2 Forms.

回答4:

import {Component} from '@angular/core';
import {NgForm} from '@angular/forms';
@Component({
    selector: 'example-app',
    template: '<form #f="ngForm" (ngSubmit)="onSubmit(f)" novalidate>
        <input name="first" ngModel required #first="ngModel">
        <input name="last" ngModel>
        <button>Submit</button>
    </form>
    <p>First name value: {{ first.value }}</p>
    <p>First name valid: {{ first.valid }}</p>
    <p>Form value: {{ f.value | json }}</p>
    <p>Form valid: {{ f.valid }}</p>',
})
export class SimpleFormComp {
    onSubmit(f: NgForm) {

        // some stuff

        f.resetForm();
    }
}

回答5:

Make a Call clearForm(); in your .ts file

Try like below example code snippet to clear your form data.

clearForm() {

this.addContactForm.reset({
      'first_name': '',
      'last_name': '',
      'mobile': '',
      'address': '',
      'city': '',
      'state': '',
      'country': '',
       'zip': ''
     });
}

回答6:

To angular version 4, you can use this:

this.heroForm.reset();

But, you could need a initial value like:

ngOnChanges() {
 this.heroForm.reset({
  name: this.hero.name, //Or '' to empty initial value. 
  address: this.hero.addresses[0] || new Address()
 });
}

It is important to resolve null problem in your object reference.

reference link, Search for "reset the form flags".

回答7:

Here is how I do it in Angular 7.3

// you can put this method in a module and reuse it as needed
resetForm(form: FormGroup) {

    form.reset();

    Object.keys(form.controls).forEach(key => {
      form.get(key).setErrors(null) ;
    });
}

There was no need to call form.clearValidators()

回答8:

There is a new discussion about this (https://github.com/angular/angular/issues/4933). So far there is only some hacks that allows to clear the form, like recreating the whole form after submitting: https://embed.plnkr.co/kMPjjJ1TWuYGVNlnQXrU/

回答9:

I found another solution. It's a bit hacky but its widely available in angular2 world.

Since *ngIf directive removes the form and recreates it, one can simply add an *ngIf to the form and bind it to some sort of formSuccessfullySentvariable. => This will recreate the form and therefore reset the input control statuses.

Of course, you have to clear the model variables also. I found it convenient to have a specific model class for my form fields. This way i can reset all fields as simple as creating a new instance of this model class. :)

回答10:

Here's how I do it Angular 8:

Get a local reference of your form:

<form name="myForm" #myForm="ngForm"></form>

@ViewChild('myForm', {static: false}) myForm: NgForm;

And whenever you need to reset the form, call resetForm method:

this.myForm.resetForm();

You will need FormsModule from @angular/forms for it to work. Be sure to add it to your module imports.

回答11:

Hm, now (23 Jan 2017 with angular 2.4.3) I made it work like this:

newHero() {
    return this.model = new Hero(42, 'APPLIED VALUE', '');
}
<button type="button" class="btn btn-default" (click)="heroForm.resetForm(newHero())">New Hero</button>

回答12:

Below code works for me in Angular 4

import { FormBuilder, FormGroup, Validators } from '@angular/forms';
export class RegisterComponent implements OnInit {
 registerForm: FormGroup; 

 constructor(private formBuilder: FormBuilder) { }   

 ngOnInit() {
    this.registerForm = this.formBuilder.group({
      empname: [''],
      empemail: ['']
    });
 }

 onRegister(){
    //sending data to server using http request
    this.registerForm.reset()
 }

}