我正在學習Ionic 3,並且在嘗試製作自定義驗證程序時遇到此錯誤,該驗證程序檢查唯一用戶名。我已盡力,但無法解決此問題。如何解決「錯誤:未捕獲(承諾):錯誤:沒有供應商」在Ionic 3中的錯誤
CustomValidators.ts
import { Directive, Input } from '@angular/core';
import { FormControl, Validator, AbstractControl } from '@angular/forms';
import { Http, Response, Headers, RequestOptions } from '@angular/http';
import {Observable} from 'rxjs/Rx';
export class CustomValidators {
constructor(public http: Http){}
public hasUniqueEmail(
control: FormControl,
){
return this.http.get('assets/users.json')
.map(res => res.json())
.catch((error:any) => Observable.throw(error.json().error || 'Server error'));
}
}
signup.ts
import { Component } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { CustomValidators } from '../../components/CustomValidators';
/**
* Generated class for the SignupPage page.
*
* See http://ionicframework.com/docs/components/#navigation for more info
* on Ionic pages and navigation.
*/
@IonicPage()
@Component({
selector: 'page-signup',
templateUrl: 'signup.html',
})
export class SignupPage {
private sform : FormGroup;
constructor(
private formBuilder: FormBuilder,
private myValidator: CustomValidators,
){
this.sform = this.formBuilder.group({
name: ['', Validators.compose([Validators.maxLength(30), Validators.pattern('[a-zA-Z ]*'), Validators.required])],
email: ['', Validators.compose([Validators.email,this.myValidator.hasUniqueEmail])],
password: ['',Validators.required ],
});
}
logForm() {
}
}
這是我得到的錯誤:
"Uncaught (in promise): Error: No provider for CustomValidators!
Error
at Error (native)
at injectionError (http://localhost:8100/build/main.js:1583:86)
at noProviderError (http://localhost:8100/build/main.js:1621:12)
at ReflectiveInjector_._throwOrNull (http://localhost:8100/build/main.js:3122:19)
at ReflectiveInjector_._getByKeyDefault (http://localhost:8100/build/main.js:3161:25)
at ReflectiveInjector_._getByKey (http://localhost:8100/build/main.js:3093:25)
at ReflectiveInjector_.get (http://localhost:8100/build/main.js:2962:21)
at NgModuleInjector.get (http://localhost:8100/build/main.js:3909:52)
at resolveDep (http://localhost:8100/build/main.js:11369:45)
at createClass (http://localhost:8100/build/main.js:11225:91)"
CustomValidators是一個組件,一個服務,一個管道,類應該表示什麼? – Baruch