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

Angular 6: Can't bind to 'formGroup' since it isn't a known property of 'form'?

提问by Shubham Verma

I have worked with form builder in angular 2/4, But now I am using it in angular 6. I have seen this question (Can't bind to 'formGroup' since it isn't a known property of 'form') but it was for angular 2. I doing exact same against angular 4 but I am getting this error. Please help: my code are:

我曾在 angular 2/4 中使用表单构建器，但现在我在 angular 6 中使用它。我见过这个问题（无法绑定到 'formGroup'，因为它不是 'form' 的已知属性）但是它是针对 angular 2 的。我对 angular 4 做的完全一样，但我收到了这个错误。请帮助：我的代码是：

app.module.ts: ( I have exported FormsModule & ReactiveFormsModule) :

app.module.ts: ( 我已经导出 FormsModule & 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:

登录.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: ( Something like this)

login.component.html : ( 像这样的东西）

 <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>

回答by Prashant Pimpale

Add below code in your app.module.ts:

在您的app.module.ts:

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

and in imports array:

并在导入数组中：

imports: [
        BrowserModule,
        FormsModule,
        ReactiveFormsModule
    ]

The FormGroupis a selector for the FormGroupDirectiveDirective which mainly used to Binds an existing FormGroupto a DOM element and FormGroupDirectiveis available in the ReactiveFormsModulemodule.

的FormGroup是对于一个选择FormGroupDirective指令，它主要用于绑定的现有FormGroup的DOM元素和FormGroupDirective是可用的在ReactiveFormsModule模块。

回答by MetaSimian

So fiddling around with the same frustrating issue -- a clean angular-cli install and a custom subcomponent/module (component.html... ) and the same error ("Can't bind to 'formGroup' since it isn't a known property of 'form' "). Angular CLI: 7.2.3, Node: 10.9.0, OS: win32 x64, Angular: 7.2.2

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

I finally got it to workbased on the above but with a twist I put the FormsModule & ReactiveFormsModule imports in app-routing.module.ts(not app.module.ts) + the subcomponent's ts (in my case: forms-demo.component.ts) :

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
....

Afterward ng build/serve worked without any errors.

之后 ng build/serve 工作没有任何错误。

I'm not an Angular expert but my guess is that the v7 approach whereby app.module.ts delegates to app-routing, that latter file is where the app & component imports & dependencies take place.... YMMV but hopefully it helps.

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.

回答by Zameer Fouzan

Similar to @gloomy.penguin's answer in comment, but a different scenario with the same error.

与@gloomy.penguin 在评论中的回答类似，但具有相同错误的不同场景。

In my case, I was using a second module and its own routing file.

就我而言，我使用的是第二个模块和它自己的路由文件。

│   app-routing.module.ts
│   app.module.ts
│
└───second-module
    │   second-routing-module.module.ts
    │   second.module.ts
    │
    └───component-1

I had to import the following in second.module.tsrather than app-routing.module.ts

我不得不在second.module.ts而不是app-routing.module.ts 中导入以下内容

import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { BrowserModule } from '@angular/platform-browser';
....
@NgModule({
  imports: [
CommonModule,    
FormsModule,
ReactiveFormsModule,
BrowserModule
]})

anyone using a second module, please follow this.

任何使用第二个模块的人，请按照此操作。

回答by James Siva

import these things in your appmodule.ts

imports: [
        BrowserModule,
        FormsModule,
        ReactiveFormsModule
    ],

回答by jbooker

Update app.module.ts as follows in belows diff

在下面的差异中更新 app.module.ts 如下

回答by hritika panchratan

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { BrowserAnimationsModule } from "@angular/platform-browser/animations";
import { MatButtonModule, MatCheckboxModule , MatTableModule, MatDialogModule, MatTabsModule, MatNativeDateModule, MatInputModule, MatSelectModule, MatFormFieldModule} from "@angular/material";
import { MyDialogComponent } from './my-dialog/my-dialog.component';
import {MatDatepickerModule} from '@angular/material/datepicker';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import {NgxMaterialTimepickerModule} from 'ngx-material-timepicker';
import { CommonModule } from '@angular/common';
import { HighlightDirective } from './highlight.directive';

@NgModule({
  declarations: [
    AppComponent,
    MyDialogComponent,
    HighlightDirective,
  ],
  imports: [
    BrowserModule,
    BrowserAnimationsModule,
    MatButtonModule,
    MatCheckboxModule,
    MatTableModule,
    MatDialogModule,
    MatTabsModule,
    MatNativeDateModule,
    MatInputModule,
    MatSelectModule,
    MatDatepickerModule,
    FormsModule,
    ReactiveFormsModule,
    NgxMaterialTimepickerModule,
    CommonModule,
    MatFormFieldModule,
    AppRoutingModule
  ],

回答by Arun

Can't bind to 'formGroup' since it isn't a known property of 'form'? why means ? Answer: ' ReactiveFormsModule ' could not load in your component.you just add component name into rootmodule (app.module.ts)

无法绑定到“formGroup”，因为它不是“form”的已知属性？为什么是指？答案：“ ReactiveFormsModule ”无法加载到您的组件中。您只需将组件名称添加到 rootmodule (app.module.ts) 中

SOLUTION:

解决方案：

**WITHOUT ROUTING**
      **app.modules.ts**
      STEP1 : import { FormsModule,ReactiveFormsModule } from '@angular/forms';
      STEP2 : check your component (AppComponent)loaded or not
               @NgModule({
                  declarations: [
                     AppComponent
                   ],
               imports: [
                 BrowserModule,
                 AppRoutingModule,
                 ReactiveFormsModule,
                 FormsModule
                ],
             providers: [],
             bootstrap: [AppComponent]
            })
      app.component.html
         use and check <form [formGroup]="registerForm"></form>



 **WITH ROUTING**
    Eg;I have 2 files - form.component.html,form.component.ts

             STEP1:Import and add component(FormComponent) loaded or not in app.component.ts(rootcomponent) below here.
import { FormComponent } from "./form/form.component";
                     @NgModule({
                          declarations: [
                             AppComponent,
                             FormComponent
                           ],
                       imports: [
                         BrowserModule,
                         AppRoutingModule,
                         ReactiveFormsModule,
                         FormsModule
                        ],
                     providers: [],
                     bootstrap: [AppComponent]
                    });