尝试实现 Spinner 时出现异常

Question

我正在按照https://www.npmjs.com/package/ngx-spinner 的说明在我的应用程序中实现微调器，但显然我做错了。

这是我的打字稿模块。一切正常，但是即使我在 ngOnInit 中显示它并将其隐藏在 getFacilities 的回调中，我也没有看到任何微调器。 （我知道这些方法正在执行，因为我正在将数据显示到页面上。）

import { Component } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { NgxSpinnerService } from "ngx-spinner";
import { Portfolio} from '../models/Portfolio';
import { Facility } from '../models/Facility';
import 'rxjs/add/operator/map';


@Component({
    selector: 'app-member-component',
    templateUrl: './member.component.html'
})
export class MemberComponent {

    constructor(private http: HttpClient, private spinner: NgxSpinnerService ) { }

    public SelectedPortfolio: Portfolio = new Portfolio;
    public Portfolios: Portfolio[] = [] ;

    public SelectedFacility: Facility = new Facility;
    public Facilities: Facility[] = [];

    public UILock: boolean;

    ngOnInit() {

        // call the method on initial load of page to bind dropdown   

        this.spinner.show();
        this.UILock = true;

        this.SelectedPortfolio.name = "Select Portfolio";
        this.SelectedPortfolio.id = 0;

        this.SelectedFacility.name = "<No Portfolio Selected>";
        this.SelectedFacility.id = 0;

        this.getPortfolios();
    }

    public selectPortfolio(portfolio: Portfolio) {

        this.SelectedPortfolio = portfolio;

        this.getFacilities();
    }

    public selectFacility(facility: Facility) {

        this.SelectedFacility = facility;
    }

    private getPortfolios() {

        this.UILock = true;

        this.http.get<Portfolio[]>('https://localhost:44319/api/portfolio').subscribe((portfolios: Portfolio[]): void =>
          {
            this.Portfolios = portfolios;
            this.selectPortfolio(portfolios[0]);
          }
        );
    }

    private getFacilities() {

        this.http.get<Portfolio[]>('https://localhost:44319/api/portfolio/' + this.SelectedPortfolio.id).subscribe((facilities: Facility[]): void =>
            {
              this.Facilities = facilities;
              this.selectFacility(facilities[0]);
              this.UILock = false;
              this.spinner.hide();
            }
        );
    }
}

只要我将以下内容添加到我的 html 模板中，一切都会崩溃。

<ngx-spinner bdColor="rgba(51,51,51,0.8)"
             size="medium"
             color="#fff"
             type="ball-scale-multiple">
  <p style="font-size: 20px; color: white">Loading...</p>
</ngx-spinner>

页面未加载，我看到以下异常：

ERROR Error: Uncaught (in promise): NullInjectorError: StaticInjectorError(AppModule)[NgxSpinnerComponent -> ChangeDetectorRef]: 
  StaticInjectorError(Platform: core)[NgxSpinnerComponent -> ChangeDetectorRef]: 
    NullInjectorError: No provider for ChangeDetectorRef!
NullInjectorError: StaticInjectorError(AppModule)[NgxSpinnerComponent -> ChangeDetectorRef]: 
  StaticInjectorError(Platform: core)[NgxSpinnerComponent -> ChangeDetectorRef]: 
    NullInjectorError: No provider for ChangeDetectorRef!
    at NullInjector.get (core.js:1354)
    at resolveToken (core.js:1681)
    at tryResolveToken (core.js:1607)
    at StaticInjector.get (core.js:1470)
    at resolveToken (core.js:1681)
    at tryResolveToken (core.js:1607)
    at StaticInjector.get (core.js:1470)
    at resolveNgModuleDep (core.js:23104)
    at NgModuleRef_.get (core.js:24192)
    at resolveDep (core.js:24722)
    at resolvePromise (zone-evergreen.js:797)
    at resolvePromise (zone-evergreen.js:754)
    at zone-evergreen.js:858
    at ZoneDelegate.invokeTask (zone-evergreen.js:391)
    at Object.onInvokeTask (core.js:30873)
    at ZoneDelegate.invokeTask (zone-evergreen.js:390)
    at Zone.runTask (zone-evergreen.js:168)
    at drainMicroTaskQueue (zone-evergreen.js:559)

这是我的 app.module.ts：

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
import { RouterModule } from '@angular/router';
import { NgxSpinnerModule } from "ngx-spinner";

import { AppComponent } from './app.component';
import { NavMenuComponent } from './nav-menu/nav-menu.component';
import { HomeComponent } from './home/home.component';
import { ApiAuthorizationModule } from 'src/api-authorization/api-authorization.module';
import { AuthorizeGuard } from 'src/api-authorization/authorize.guard';
import { AuthorizeInterceptor } from 'src/api-authorization/authorize.interceptor';
import { MemberComponent } from './member/member.component';

@NgModule({
    declarations: [
        AppComponent,
        NavMenuComponent,
        HomeComponent,
        MemberComponent,
    ],
    imports: [
        BrowserModule.withServerTransition({ appId: 'ng-cli-universal' }),
        HttpClientModule,
        FormsModule,
        ApiAuthorizationModule,
        NgxSpinnerModule,
        RouterModule.forRoot([
            { path: '', component: HomeComponent, pathMatch: 'full' },
            { path: 'member', component: MemberComponent, canActivate: [AuthorizeGuard] },
        ])
    ],
    providers: [
        { provide: HTTP_INTERCEPTORS, useClass: AuthorizeInterceptor, multi: true }
    ],
    bootstrap: [AppComponent]
})
export class AppModule { }

感谢您的建议！

也许我的 package.json 是相关的？

{
  "name": "cashflow",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "build:ssr": "ng run Cashflow:server:dev",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "8.0.0",
    "@angular/common": "8.0.0",
    "@angular/compiler": "8.0.0",
    "@angular/core": "8.0.0",
    "@angular/forms": "8.0.0",
    "@angular/platform-browser": "8.0.0",
    "@angular/platform-browser-dynamic": "8.0.0",
    "@angular/platform-server": "8.0.0",
    "@angular/router": "8.0.0",
    "@nguniversal/module-map-ngfactory-loader": "8.0.0-rc.1",
    "aspnet-prerendering": "^3.0.1",
    "bootstrap": "^4.3.1",
    "core-js": "^2.6.5",
    "jquery": "3.4.1",
    "oidc-client": "^1.9.0",
    "popper.js": "^1.14.3",
    "rxjs": "^6.4.0",
    "zone.js": "~0.9.1"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "^0.800.6",
    "@angular/cli": "8.0.6",
    "@angular/compiler-cli": "8.0.0",
    "@angular/language-service": "8.0.0",
    "@types/jasmine": "~3.3.9",
    "@types/jasminewd2": "~2.0.6",
    "@types/node": "~11.10.5",
    "codelyzer": "^5.0.1",
    "jasmine-core": "~3.3.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "^4.0.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.5",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "typescript": "3.4.5"
  },
  "optionalDependencies": {
    "node-sass": "^4.9.3",
    "protractor": "~5.4.0",
    "ts-node": "~5.0.1",
    "tslint": "~5.9.1"
  }
}

Answer 1

问题是，我在项目中有两个 node_modules 文件夹。一个在正确的位置，在 ClientApp（这是 Angular 应用程序“存在”的地方）中，另一个在 Web 应用程序的根目录（错误！）。显然有冲突。

我现在明白，在构建这样的应用程序时，我实际上是在构建两个应用程序——一个在服务器上（用 C# 编写），一个在客户端（Angular / Typescript）。 Visual Studio 提供了一个统一的编辑器环境，我们可以在其中同时处理两个应用程序，但它仍然是两个独立的应用程序。最初，在我真正知道自己在做什么之前，我通过 Visual Studio 控制台窗口安装了我的 Angular 模块，但我没有意识到在安装之前手动设置文件夹位置 (cd ClientApp) 很重要包，否则它会在错误的位置结束。这是我为清理它所做的工作：

1. 从项目根目录中删除流氓 package.json、package-lock.json、angular.json。
2. 卸载了 Dependencies/NPM 下列出的所有 Angular 包
3. 从项目根目录中删除 node_modules 文件夹
4. 在 ClientApp 文件夹中运行 npm update。

现在一切正常！我什至不必更改一行代码。

Answer 2

你缺少来自 @angular/common 的 commonmodule

从 '@angular/common' 导入 { CommonModule }；

Answer 3

你可以这样处理。 Example

 showSpinner() {
    this.spinner.show();
    setTimeout(() => {
        /** spinner ends after 5 seconds */
        this.spinner.hide();
    }, 5000);
  }