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

Question

我在角度2/4中使用了表单构建器,但现在我在角度6中使用它.我已经看到了这个问题(不能绑定到'formGroup',因为它不是'form'的已知属性)但是它是针对角度2.我对角度4完全相同,但我得到了这个错误.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 { }

login.component.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 :(像这样)

 <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>

Answer 1

在您的下面添加以下代码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
    ]

Answer 2

所以摆弄同样令人沮丧的问题——一个干净的 angular-cli 安装和一个自定义的子组件/模块 (component.html...) 和同样的错误（“无法绑定到‘formGroup’，因为它不是一个'形式'的已知属性”）。Angular CLI：7.2.3，节点：10.9.0，操作系统：win32 x64，Angular：7.2.2

我终于根据上面的内容让它工作了，但是我把 FormsModule 和 ReactiveFormsModule 导入放在app-routing.module.ts（不是 app.module.ts）+ 子组件的 ts （在我的例子中：forms-demo。组件.ts）：

import { FormsModule, ReactiveFormsModule } from '@angular/forms';
....
@NgModule({
  imports: [
    RouterModule.forRoot(routes), 
    FormsModule, ReactiveFormsModule
....

之后 ng build/serve 工作没有任何错误。

我不是 Angular 专家，但我的猜测是 v7 方法 app.module.ts 委托应用程序路由，后一个文件是应用程序和组件导入和依赖项发生的地方.... YMMV 但希望它有所帮助.