请添加@ Pipe / @ Directive / @ Component注释。错误

Question

我陷入了困境。我收到这样的错误。

 compiler.es5.js:1694 Uncaught Error: Unexpected value 'LoginComponent' declared by the module 'AppModule'. Please add a @Pipe/@Directive/@Component annotation.
    at syntaxError (compiler.es5.js:1694)
    at compiler.es5.js:15595
    at Array.forEach (<anonymous>)
    at CompileMetadataResolver.webpackJsonp.../../../compiler/@angular/compiler.es5.js.CompileMetadataResolver.getNgModuleMetadata (compiler.es5.js:15577)
    at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler._loadModules (compiler.es5.js:26965)
    at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler._compileModuleAndComponents (compiler.es5.js:26938)
    at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler.compileModuleAsync (compiler.es5.js:26867)
    at PlatformRef_.webpackJsonp.../../../core/@angular/core.es5.js.PlatformRef_._bootstrapModuleWithZone (core.es5.js:4536)
    at PlatformRef_.webpackJsonp.../../../core/@angular/core.es5.js.PlatformRef_.bootstrapModule (core.es5.js:4522)
    at Object.../../../../../src/main.ts (main.ts:11)

我的登录组件看起来像这样

import { Component } from '@angular/Core';

@Component({
    selector:'login-component',
    templateUrl:'./login.component.html'
})

export class LoginComponent{}

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { CommonModule } from '@angular/common'
import { HttpModule } from '@angular/http';
import { ReactiveFormsModule} from '@angular/forms';
import { RouterModule, Routes } from '@angular/router';
import { AppComponent } from './main/app.component';

import {LoginComponent} from './login/login.component';


const appRoutes: Routes = [
  {path:'', redirectTo:'login', pathMatch:'full'},
  { path: 'home', component: AppComponent },
  { path: 'login', component: LoginComponent }
];

@NgModule({
  imports: [
    BrowserModule,
    RouterModule.forRoot(appRoutes),
  ],
  declarations: [
    AppComponent,
    LoginComponent
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

当我尝试将LoginComponent导入声明时出现此错误。我在这里错过了一些东西。

Answer 1

您在LoginComponent的文件中导入了一个拼写错误

import { Component } from '@angular/Core';

它是小写的c，而不是大写

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

Answer 2

不是上面具体示例的解决方案，但可能有很多原因导致您收到此错误消息。当我意外地将共享模块添加到模块声明列表而不是导入时，我得到了它。

在app.module.ts中：

import { SharedModule } from './modules/shared/shared.module';

@NgModule({
  declarations: [
     // Should not have been added here...
  ],
  imports: [
     SharedModule
  ],

Answer 3

如果执行了任何错误导入，则会出现Above错误。例如，有时可以在TestBed.configureTestingModule中添加Service文件。还可以在导入Material组件时进行导入

import {MatDialogModule} from '@angular/material/dialog'

不是来自

import {MatDialogModule} from '@angular/material'

Answer 4

我有一个声明没有styleUrls属性的组件，如下所示：

@Component({
    selector: 'app-server',
    templateUrl: './server.component.html'
})

代替：

@Component({
    selector: 'app-server',
    templateUrl: './server.component.html',
    styleUrls: ['./server.component.css']
})

添加styleUrls属性解决了这个问题。

Answer 5

如果要在该模块中导出另一个类，请确保它不在@Component和ClassComponent之间。例如：

@Component({ ... })

export class ExampleClass{}

export class ComponentClass{}  --> this will give this error.

固定：

export class ExampleClass{}

@Component ({ ... })

export class ComponentClass{}