无法解析AdminProductsComponent的所有参数

Question

我犯了个奇怪的错误：-

错误:无法解析AdminProductsComponent的所有参数：(?，对象对象，对象对象)。

我找不到错误，错误只显示在这个组件上，而不是其他组件，尽管它们在同一个组件中。请帮帮我！

admin-products.component.ts

import { Component, OnInit } from '@angular/core';
import { ItemsService } from 'src/app/services/items.service';
import { ProductsService } from 'src/app/services/products.service';
import { Router, ActivatedRoute } from '@angular/router';
import { Subscription } from 'rxjs';

@Component({
  selector: 'app-admin-products',
  templateUrl: './admin-products.component.html',
  styleUrls: ['./admin-products.component.scss']
})
export class AdminProductsComponent implements OnInit {
  subscription: Subscription
  subscription1: Subscription

  constructor(
    public iservice: ItemsService, 
    private prservice: ProductsService, 
    private router: Router, 
    private route: ActivatedRoute
  ) {}

  ngOnInit() {
    this.iservice.getdata().subscribe(data => {
      this.alldata = data
    });
  }

  onclick(el) {
    this.prservice.editchanged.next(el)
    this.router.navigate(['admin/products/edit'])
  }
}

app.module.ts

import { UserResolver } from './home/home.resolver';
import { AuthGuard } from './home/auth-guard';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { MDBBootstrapModule } from 'angular-bootstrap-md';
import { AngularFireModule } from 'angularfire2';
import { AngularFirestoreModule } from 'angularfire2/firestore';
import { AngularFireAuthModule } from 'angularfire2/auth';
import { environment } from '../environments/environment';
import { AppComponent } from './app.component';

import { HomeComponent } from './home/home.component';
import { AppRouting } from './app.routes';
import { UserService } from './auth/user.service';
import { AuthService } from './auth/auth.service';

import { ItemsService } from './services/items.service';
import { AdminOrdersComponent } from './admin/admin-orders/admin-orders.component';
import { AdminProductsComponent } from './admin/admin-products/admin-products.component';

import { ProductsService } from './services/products.service';
import { HttpModule } from '@angular/http';
import { AdminEditComponent } from './admin/admin-edit/admin-edit.component';

@NgModule({
  declarations: [
    AppComponent,
    AdminOrdersComponent,
    AdminProductsComponent,
    AdminEditComponent,
  ],
  imports: [
    AngularFireModule.initializeApp(environment.firebase),
    AngularFirestoreModule, // imports firebase/firestore, only needed for database features
    AngularFireAuthModule, // imports firebase/auth, only needed for auth features
    BrowserModule,
    FormsModule,
    ReactiveFormsModule,
    AppRouting,
    MDBBootstrapModule.forRoot(),
    HttpModule,
  ],
  providers:[
    AuthGuard, 
    UserService, 
    AuthService, 
    UserResolver,
    ItemsService, 
    ProductsService
  ],
  bootstrap: [AppComponent]
})
export class AppModule {}

app.routes.ts

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';

import { UserResolver } from './home/home.resolver';
import { AuthGuard } from './home/auth-guard';
import { AdminProductsComponent } from "./admin/admin-products/admin-products.component";
import { AdminOrdersComponent } from "./admin/admin-orders/admin-orders.component";
import { AdminEditComponent } from "./admin/admin-edit/admin-edit.component";

const rootRouterConfig: Routes = [
  { path: '', redirectTo: 'login', pathMatch: 'full' },
  { path: 'login', component: LoginComponent, canActivate: [AuthGuard] },
  { path: 'register', component: RegisterComponent, canActivate: [AuthGuard] },
  { path: 'home', component: HomeComponent, resolve: { data: UserResolver } },
  { path: 'admin/products', component: AdminProductsComponent },
  { path: 'admin/products/edit', component: AdminEditComponent },
  { path: 'admin/orders', component: AdminOrdersComponent }
];

@NgModule({
  imports: [
    RouterModule.forRoot(rootRouterConfig)
  ],
  exports: [RouterModule]
})
export class AppRouting { }

Answer 1

在AdminProductsComponent的构造函数中，

constructor(
    public iservice: ItemsService, 
    private prservice: ProductsService, 
    private router: Router, 
    private route: ActivatedRoute
  ) {}

您可以注入两个服务，名为ItemsService和ProductsService。在大多数情况下，您可能忘记为这两个服务添加一个'@Injectable()‘注释。