Angular:如何在单击按钮时将FormControl动态添加到FormArray [英] Angular: How to dynamically add FormControl to FormArray on button click
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问题描述
如何在formarray中动态添加formcontrol(option)?我想添加问题formarray.单击按钮应显示.我正在使用角度7.
How can I add a formcontrol(option) dynamically in formarray? I want to add in questions formarray. Onbutton click it should display. I'm using angular 7.
//ngOnInit creating form
ngOnInit() {
this.quizForm = this.fb.group({
questions: this.fb.array([]),
questions2: this.fb.array([]),
});
}
//creating formcontrol
createItem(): FormGroup {
return this.fb.group({
ques: '',
});
}
//pushing code
genField() {
this.message = true;
this.questions = this.quizForm.get('questions') as FormArray;
this.questions.push(this.createItem());
}
这是我的HTML代码.我想在单击按钮时动态添加表单控件选项，并且表单控件应位于formArrayName ="questions"之内.
Here's my HTML code. I want to add form control option dynamically on button click and form control should be inside the formArrayName="questions".
<form [formGroup]="quizForm"
class="adjust-form">
<div formArrayName="questions"
*ngFor="let item of quizForm.get('questions').controls; let i = index;">
<div class="col-md-10 col-sm-6 mt-3 mb-3"
[formGroupName]="i">
<label>{{i +1}} - {{question}} </label>
<i class="flaticon-delete"
(click)="quizForm.get('questions').controls.splice(i,1) "
style="font-size: 9px;padding-left: 80px;"></i>
<div class="row">
<input type="text"
class="form-control col-10"
[(ngModel)]="item.ques"
formControlName="ques"
placeholder="Enter your question"
required>
<button *ngIf="i == 0"
(click)="genField()"
type="button"
class="btn btn-secondary btn-elevate btn-circle btn-icon ml-4">
<i class="flaticon2-plus"></i></button>
</div>
<div *ngIf="item.touched && item.invalid"
class="kt-font-danger text-left">
<p>required</p>
</div>
</div>
</div>
推荐答案
此示例将电子邮件字段动态添加到反应形式.这将使用户能够添加多个电子邮件地址(例如，住所和公司).
This example dynamically adds email fields to a reactive form. This would be used to enable users to add multiple email addresses (e.g. Home and Work).
This demo has the following dependencies: Angular 8, Angular Material, Bootstrap 4
constructor(private formBuilder: FormBuilder) { }
ngOnInit() {
this.emailForm = this.formBuilder.group({
emails: this.formBuilder.array([this.createEmailFormGroup()])
});
}
步骤2:定义一种动态构造新的FormGroup
的方法
Step 2: Define a method to dynamically construct new FormGroup
private createEmailFormGroup(): FormGroup {
return new FormGroup({
'emailAddress': new FormControl('', Validators.email),
'emailLabel': new FormControl('')
})
}
步骤3:定义一种将新的FormGroup动态添加到FormArray
的方法
Step 3: Define a method to dynamically add new FormGroup to the FormArray
public addEmailFormGroup() {
const emails = this.emailForm.get('emails') as FormArray
emails.push(this.createEmailFormGroup())
}
步骤4(可选):定义删除FormGroup
的方法
Step 4 (Optional): Define method to delete FormGroup
public removeOrClearEmail(i: number) {
const emails = this.emailForm.get('emails') as FormArray
if (emails.length > 1) {
emails.removeAt(i)
} else {
emails.reset()
}
}
第5步:创建HTML表单模板
<form [formGroup]="emailForm">
<div formArrayName="emails">
<div class="row" *ngFor="let email of emailForm.get('emails').controls; let i = index"
[formGroupName]="i">
请注意，在formArrayName元素内，动态电子邮件FormGroups是根据数组索引命名的.
Note that within the formArrayName element, the dynamic email FormGroups are named based on the array index.
<mat-toolbar color="primary">
Angular Form Demo - Dynamically add form controls
</mat-toolbar>
<form class="basic-container" [formGroup]="emailForm">
<div formArrayName="emails">
<div class="row" *ngFor="let email of emailForm.get('emails').controls; let i = index"
[formGroupName]="i">
<div class="col-1">
<mat-icon class="mt-3">email</mat-icon>
</div>
<mat-form-field class="col-4">
<input matInput formControlName="emailAddress" placeholder="Email" autocomplete="email">
<mat-error *ngFor="let validation of validationMsgs.emailAddress">
<div *ngIf="email.get('emailAddress').hasError(validation.type)">
{{validation.message}}
</div>
</mat-error>
</mat-form-field>
<mat-form-field class="col-4">
<mat-label>Label</mat-label>
<mat-select formControlName="emailLabel">
<mat-option *ngFor="let label of emailLabels" [value]="label">
{{label}}
</mat-option>
</mat-select>
</mat-form-field>
<div class="col-3">
<button class="float-left" mat-icon-button color="primary" aria-label="Remove/clear"
(click)="removeOrClearEmail(i)" matTooltip="Remove">
<mat-icon>highlight_off</mat-icon>
</button>
<button class="float-left" mat-icon-button color="primary" aria-label="Add"
(click)="addEmailFormGroup()" matTooltip="Add">
<mat-icon>add_circle_outline</mat-icon>
</button>
</div>
</div>
</div>
</form>
最终组件
import {Component} from '@angular/core';
import {FormBuilder, FormArray, FormControl, FormGroup, Validators} from '@angular/forms';
@Component({
selector: 'form-app',
templateUrl: 'app.component.html'
})
export class AppComponent {
public emailForm: FormGroup;
public emailLabels = ['Home', 'Work', 'Other'];
public validationMsgs = {
'emailAddress': [{ type: 'email', message: 'Enter a valid email' }]
}
constructor(private formBuilder: FormBuilder) { }
ngOnInit() {
this.emailForm = this.formBuilder.group({
emails: this.formBuilder.array([this.createEmailFormGroup()])
});
}
public addEmailFormGroup() {
const emails = this.emailForm.get('emails') as FormArray
emails.push(this.createEmailFormGroup())
}
public removeOrClearEmail(i: number) {
const emails = this.emailForm.get('emails') as FormArray
if (emails.length > 1) {
emails.removeAt(i)
} else {
emails.reset()
}
}
private createEmailFormGroup(): FormGroup {
return new FormGroup({
'emailAddress': new FormControl('', Validators.email),
'emailLabel': new FormControl('')
})
}
}
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