[英]Angular Reactive form Validation for dynamic forms inside *ngFor
I am new to angular when I was trying to put the form validation to the text field form was present inside *ngFor
loop, So validation is working but it shows to every field but I want validation the particular field only , so please help me How to put the validation to the particular form field. 当我尝试对
*ngFor
循环中存在的文本字段进行表单验证时,我是*ngFor
,所以验证工作正常,但它向每个字段显示,但我只想验证特定字段,所以请帮助我将验证放入特定的表单字段。
**HTML**
<div class="container" *ngFor="let post of posts; let i = index">
<div class="row">
<div class="col-md-12" style="display: block; ">
<form [formGroup]="commentForm" method="post" enctype="multipart/form-data" (ngSubmit)="comment_Submit(post.user_id, post.post_id,
commentForm)">
<div class="form-group">
<input type="text" class="form-control" name="comment{{i}}" formControlName="comment" id="comment"
placeholder="Enter comments" cols="40" rows="5" spellcheck="true"
style="width:100%; height: auto; border: 1px solid #ada5a5; border-radius: 4px; outline: none; user-select: text; white-space: pre-wrap; overflow-wrap: break-word; "
[ngClass]="{'form-control': true,
'is-invalid': !f.comment.valid,
'is-valid':f.comment.valid}">
<div *ngIf="f.comment.errors?.minlength && f.comment.touched" class="text-danger">Comment
should be at
least 2 characters.</div>
</div>
<button type="submit" class="btn-sm btn-success" [disabled]="!commentForm.valid">Comment</button>
</form>
</div>
</div>
</div>
**TypeScript**
export class PostsComponent implements OnInit {
get f() { return this.commentForm.controls; }
constructor(private userService: UserService, private formBuilder: FormBuilder,
private alerts: AlertsService) {
this.commentFormValidation();
}
commentForm: FormGroup;
ngOnInit() { }
commentFormValidation() {
this.commentForm = this.formBuilder.group({
comment: [null, [Validators.required, Validators.minLength(2)]]
});
}
Your posts
all share the one and same form. 您的
posts
都共享一个相同的表格。 If you have n
amount of posts
, you need n
amount of forms. 如果您有
n
posts
,则需要n
个表格。 We can achieve this by creating an array (just a JS array) of formgroups, the same length that your posts
array is... 我们可以通过创建一个表单组数组(只是一个JS数组)来实现这一点,该数组的长度与
posts
数组的长度相同...
formsArr = [];
constructor(private fb: FormBuilder) { }
ngOnInit() {
this.posts.forEach((x) => {
this.formsArr.push(this.fb.group({
comment: this.fb.control('', [Validators.required, Validators.minLength(2)])
}))
})
}
Then in your template you iterate formsArr
. 然后,在您的模板中,迭代
formsArr
。 You probably need access to some stuff in your posts
array... so we add the index in iteration, therefore you can access the specific post
with posts[i]
. 您可能需要访问
posts
数组中的某些内容...因此我们在迭代中添加了索引,因此您可以使用posts[i]
访问特定的post
。 Also remove method="post"
from your form: 同时从您的表单中删除
method="post"
:
<div *ngFor="let a of formsArr; let i = index">
<form [formGroup]="a" (ngSubmit)="onSubmit(a.value, posts[i].user_id)">
<input formControlName="comment" />
<small *ngIf="a.hasError('minlength', 'comment') && a.get('comment').touched">
Needs to be 2 letters
</small>
<button type="submit" [disabled]="!a.valid">Comment</button>
</form>
</div>
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