我尝试制作自定义验证程序,当用户在文本上留出空格时会向用户发送消息,但我收到此错误。
这是组件的html
<form [formGroup]='form'>
<div class="form-group">
<label for="username">Username</label>
<input
formControlName='username'
id="username"
type="text"
class="form-control">
<div *ngIf="username.touched && username.touched" class="alert alert-danger">
<div *ngIf="username.errors.required"> You need to enter user name</div>
<div *ngIf="username.errors.minlength"> Min Length is
{{ username.errors.minLength.requiredLength}}
</div>
<div *ngIf="UserNameValiditors.removeSpaceFromUserName">
removeSpaceFromUserName </div>
</div>
</div>
<div class="form-group">
<label for="password">Password</label>
<input
formControlName='password'
id="password"
type="text"
class="form-control">
</div>
<button class="btn btn-primary" type="submit">Sign Up</button>
</form>
这是自定义验证器类
import { AbstractControl, ValidationErrors } from "@angular/forms";
export class UserNameValiditors {
static removeSpaceFromUserName(control: AbstractControl): ValidationErrors | null {
if ((control.value as string).indexOf(' ') >= 0) {
return {
removeSpaceFromUserName: true
};
}
else {
return null;
}
}
}
import { Component } from '@angular/core';
import { FormControl , FormGroup , Validators } from "@angular/forms";
import { UserNameValiditors } from './UserNameValditors';
@Component({
selector: 'signup-form',
templateUrl: './signup-form.component.html',
styleUrls: ['./signup-form.component.css']
})
export class SignupFormComponent {
form= new FormGroup(
{
username : new FormControl('',
[
Validators.required,
Validators.minLength(3) ,
UserNameValiditors.removeSpaceFromUserName
]) ,
password : new FormControl('',Validators.required)
});
get username()
{
return this.form.get('username');
}
}
答案 0 :(得分:0)
使用hasError()
检查表单上是否存在某些错误。
html代码
<div *ngIf="username.hasError('required')"> You need to enter user name</div>
<div *ngIf="username.hasError('minlength')"> Min Length is {{ username.hasError('minLength')}}
</div>f
<div *ngIf="username.hasError('removeSpaceFromUserName')">
removeSpaceFromUserName </div>
</div>
您的工作代码为here
答案 1 :(得分:0)
您可以尝试使用此解决方案。
我已在 Stackblitz
上创建了一个演示app.component.ts
myForms: FormGroup;
constructor(fb: FormBuilder) {
this.myForms = fb.group({
username: [null, Validators.compose([
Validators.required, Validators.minLength(3), usernameValidator])],
password: [null, [
Validators.required]]
});
}
app.component.html
<form [formGroup]="myForms">
<label>User Name :
<input type="text" formControlName="username">
</label><br>
<div class="errors" *ngIf="myForms.get('username').invalid && (myForms.get('username').touched || myForms.get('username').dirty)">
<div *ngIf="myForms.get('username').hasError('required')">
username is required
</div>
<div *ngIf="myForms.get('username').errors.minlength">
username must be at least 3 characters
</div>
<div class="error-text" *ngIf="myForms.get('username').hasError('removeSpaceFromUserName')">
removeSpaceFromUserName
</div>
</div>
<div class="form-group">
<label for="password">Password</label>
<input
formControlName='password'
id="password"
type="text"
class="form-control">
</div>
<button class="btn btn-primary" type="submit">Sign Up</button>
</form>