问无法绑定到'formGroup‘，因为它不是Angular 11上'form’的已知属性，并且ReactiveFormsModule已导入

EN

- src
-- modules
--- authentication
---- login
------ login.component.ts
------ login.component.html
---- authentication.module.ts
-- app.module.ts

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

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    HttpClientModule,
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

import { NgModule } from '@angular/core';
import { LoginComponent } from './login/login.component';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { BrowserModule } from '@angular/platform-browser';

@NgModule({
  declarations: [
    LoginComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    ReactiveFormsModule
  ]
})
export class AuthenticationModule { }

...
    <form [formGroup]="form" (ngSubmit)="onSubmit()" class="form-validate is-alter" autocomplete="off">
...

import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { AuthService } from 'src/app/services/auth.service';
import { Router, ActivatedRoute } from '@angular/router';
import { first } from 'rxjs/operators';

@Component({ selector: 'app-login', templateUrl: './login.component.html' })
export class LoginComponent implements OnInit {
  form!:FormGroup;
  loading = false;
  submitted = false;

  constructor(
      private formBuilder: FormBuilder,
      private authService: AuthService,
      private router: Router,
      private route: ActivatedRoute
  ) { }

  ngOnInit(): void {
    this.form = this.formBuilder.group({
      username: [ '', [ Validators.required ] ],
      password: [ '', [ Validators.required ] ]
    })
  }

  get f() { return this.form.controls }

  showingPassword = false;
  
  loginInformation = {
    username: '',
    password: ''
  };

  onSubmit() {
    this.submitted = true;
    
    console.log( this.form.invalid );
    console.log( this.f.username.errors );
    console.log( this.f.password.errors );
    console.log( this.form.errors );

    if ( this.form.invalid ) return;
    
    this.loading = true;

    console.log( this.f.username.value );
    console.log( this.f.password.value );
    return;

    this.authService.login( this.f.username.value, this.f.password.value )
      .pipe(first())
      .subscribe({
        next: () => {
          const returnUrl = this.route.snapshot.queryParams['returnUrl'] || '/';
          this.router.navigateByUrl(returnUrl);
        }, error: ( error: any ) => {
          console.log( error );
          this.loading = false;
        }
      })
  }
}