Component is not part of any NgModule or the module has not been imported into your module

I am building an angular 4 application. I am getting error

Error:Component HomeComponent is not part of any NgModule or the module has not been imported into your module.

I have created HomeModule and HomeComponent. Which one do I need to refer to the AppModule? I am a bit confused. Do I need to refer HomeModule or HomeComponent? Ultimately what I am looking for is when the user clicks the Home menu, he should be directed to the home.component.html which will be rendered on the index page.

App.module is:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http'

import { AppComponent } from './app.component';
import { NavbarComponent } from './navbar/navbar.component';
import { TopbarComponent } from './topbar/topbar.component';
import { FooterbarComponent } from './footerbar/footerbar.component';
import { MRDBGlobalConstants } from './shared/mrdb.global.constants';
import { AppRoutingModule } from './app.routing';
import { HomeModule } from './Home/home.module';

@NgModule({
  declarations: [
    AppComponent,
    FooterbarComponent,
    TopbarComponent,
    NavbarComponent

  ],
  imports: [
    BrowserModule,
    HttpModule,
    AppRoutingModule,
    HomeModule

  ],
  providers: [MRDBGlobalConstants],
  bootstrap: [AppComponent]
})
export class AppModule { }

HomeModule is:

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { HomeComponent } from './home.component';

@NgModule({
  imports: [
    CommonModule
  ],
  exports: [HomeComponent],
  declarations: [HomeComponent]
})
export class HomeModule { }

HomeComponent is:

import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'app-home',
  templateUrl: './home.component.html',
  styleUrls: ['./home.component.css']
})
export class HomeComponent implements OnInit {

  constructor() { }

  ngOnInit() {
  }

}

Solution 1:

If your are not using lazy loading, you need to import your HomeComponent in app.module and mention it under declarations. Also, don't forget to remove from imports

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import {FormsModule} from '@angular/forms';
import {HttpModule} from '@angular/http'

import { AppComponent } from './app.component';
import { NavbarComponent } from './navbar/navbar.component';
import { TopbarComponent } from './topbar/topbar.component';
import { FooterbarComponent } from './footerbar/footerbar.component';
import { MRDBGlobalConstants } from './shared/mrdb.global.constants';
import {AppRoutingModule} from './app.routing';
import {HomeModule} from './Home/home.module';
// import HomeComponent here

@NgModule({
  declarations: [
    AppComponent,
    FooterbarComponent,
    TopbarComponent,
    NavbarComponent,
    // add HomeComponent here
  ],
  imports: [
    BrowserModule,
    HttpModule,
    AppRoutingModule,
    HomeModule  // remove this

  ],
  providers: [MRDBGlobalConstants],
  bootstrap: [AppComponent]
})
export class AppModule { }

Solution 2:

In my case, I only need to restart the server (that is if you're using ng serve).

It happens to me every time I add a new module while the server is running.

Solution 3:

In my case, I was missing my new generated component in the declarations at app.module.ts:

@NgModule({
  declarations: [
    AppComponent,
    ....
    NewGeneratedComponent, //this was missing
    ....
  ],
  imports: [
    ....

Solution 4:

I had the same problem. The reason was because I created a component while my server was still running. The solution is to quit the server and ng serve again.