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

Question

我在 angular 2/4 中使用过表单生成器，但现在我在 angular 6 中使用它。我已经看到这个问题 () 但它是对于 angular 2。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: (我导出了 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:

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>

Answer 1

在您的 app.module.ts 中添加以下代码：

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

并在导入数组中：

imports: [
        BrowserModule,
        FormsModule,
        ReactiveFormsModule
    ]

FormGroup is a selector for the FormGroupDirective Directive which mainly used to Binds an existing FormGroup to a DOM element and FormGroupDirective is available in the ReactiveFormsModule 模块。

Answer 2

import these things in your appmodule.ts

imports: [
        BrowserModule,
        FormsModule,
        ReactiveFormsModule
    ],

Answer 3

更新 app.module.ts 如下差异

Answer 4

所以摆弄同样令人沮丧的问题——干净的 angular-cli 安装和自定义 subcomponent/module (component.html...) 和相同的错误 ("Can't bind to 'formGroup' since it isn't a known property of 'form' "). Angular CLI：7.2.3，节点：10.9.0，OS：win32 x64，Angular：7.2.2

我终于让它工作了基于上面的但有一个转折我将 FormsModule 和 ReactiveFormsModule 导入到 app-routing.module.ts（不是 app.module.ts）+ 子组件的 ts（在我的例子中：forms-demo.component.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 app.module.ts 委托给应用程序路由的 v7 方法，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。

Answer 5

与@gloomy.penguin在评论中的回答类似，但场景不同，错误相同。

在我的例子中，我使用了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

我必须在 second.module.ts 而不是 app-routing.module.ts[=12= 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
]})

任何使用第二个模块的人，请按照此操作。

Answer 6

无法绑定到 'formGroup'，因为它不是 'form' 的已知属性？为什么意思？回答：“ReactiveFormsModule”无法在您的 component.you 中加载，只需将组件名称添加到根模块 (app.module.ts)

我的解决方案：

**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]
                    });

Answer 7

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
  ],

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'?

javascript

angular-forms

angular5

angular6

angular-formbuilder

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'?

javascript

angular-forms

angular5

angular6

angular-formbuilder

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