Angular 6：无法绑定到“formGroup”，因为它不是“form”的已知属性？

我曾在 Angular 2/4 中使用过表单生成器，但现在我在 Angular 6 中使用它。我看到了这个问题（无法绑定到“formGroup”，因为它不是“form”的已知属性 https://stackoverflow.com/questions/39152071/cant-bind-to-formgroup-since-it-isnt-a-known-property-of-form）但它是针对角度 2 的。 我对 Angular 4 做了完全相同的事情，但我收到了这个错误。请帮忙： 我的代码是：

app.module.ts：（我已导出 FormsModule 和 ReactiveFormsModule）：

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { LocalStorage } from './services/localStorage.service';
import { HttpModule, RequestOptions, XHRBackend } from '@angular/http';
import { Router } from '@angular/router';
import { RouterModule } from '@angular/router';
import { AppComponent } from './app.component';
import { routing } from './app.route';

import { FormsModule, ReactiveFormsModule }         from '@angular/forms';
import { LoginComponent } from './components/login/component';
import { ForgotComponent } from './components/forgotPassword/component';


@NgModule({
  exports: [
    FormsModule,
    ReactiveFormsModule
  ],
  declarations: [
    AppComponent,LoginComponent,ForgotComponent
  ],
  imports: [
    BrowserModule,
    routing,

  ],
  providers: [
    LocalStorage,
  ],
  bootstrap: [AppComponent],

})
export class AppModule { }

登录.组件.ts：

import { Component, ViewContainerRef, OnInit } from '@angular/core';
import { Router } from '@angular/router';
import { FormBuilder, FormGroup, Validators, NgForm } from '@angular/forms';
import { LocalStorage } from '../../services/localStorage.service';
import { environment } from '../../../environments/environment';
import { HttpService } from '../../services/http.service';
import { emailRegexp, passwordRegexp } from '../../constants';
@Component({
    selector: 'login-app',
    templateUrl: './login.component.html',
    styleUrls: ['./login.component.scss']
})

/**
 * LoginComponent class
 */

export class LoginComponent {
    private loginForm: any;
    loginValue:any;

    constructor(
        private formBuilder: FormBuilder,
        private _router: Router,
        private httpService: HttpService,
        private localStorage: LocalStorage,
    ) {
        this.loginValue = new LocalStorage(environment.localStorageKeys.ADMIN).value;

        this.loginForm = this.formBuilder.group({
            email: ['', Validators.compose([Validators.required, Validators.pattern(emailRegexp)])],
            password: ['', Validators.compose([Validators.required, Validators.minLength(8)])]
        });
    }
}

login.component.html：（类似这样的）

 <form [formGroup]="loginForm" (ngSubmit)="loginForm.valid && login()" novalidate>

 <input type="email" autocomplete="off" (focus)="focusFunction()" placeholder="User Name" formControlName="email" class="form-control">

<div class="col-12">
 <input autocomplete="off" type="password" (focus)="focusFunction()" placeholder="Password" formControlName="password" class="form-control">
 </div>

 <button [disabled]="!loginForm.valid" type="submit" class="btn btn-inverse btn-rounded btn-block">
            <div  *ngIf="!loading" class="sign-in">Sign in</div>
  </button>

  </form>

在您的中添加以下代码app.module.ts:

import { BrowserModule } from '@angular/platform-browser';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';

并在导入数组中：

imports: [
        BrowserModule,
        FormsModule,
        ReactiveFormsModule
    ]

The FormGroup https://angular.io/api/forms/FormGroup是一个选择器FormGroupDirective https://angular.io/api/forms/FormGroupDirective主要用于绑定现有的指令FormGroup https://angular.io/api/forms/FormGroup到 DOM 元素并且FormGroupDirective https://angular.io/api/forms/FormGroupDirective可以在ReactiveFormsModule https://angular.io/api/forms/ReactiveFormsModule module.