Question

我正在使用Angular CLI v1.0.0-beta.19-3来构建一个Angular 2网站。我生成我的组件如下ng g component file-upload。

我注意到生成的组件file-upload.component.ts如下所示。

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

我需要在我自己的组件中使用此组件ng2-file-upload。所以我尝试在directives装饰器上添加@Component属性，但是，我在VS Code中收到错误。

@Component({
  selector: 'file-upload',
  templateUrl: './file-upload.component.html',
  styleUrls: ['./file-upload.component.css'],
  directives: [ FILE_UPLOAD_DIRECTIVES ]
})
export class FileUploadComponent implements OnInit {
 ...
}

[ts] Argument of type '{ selector: string; templateUrl: string; styleUrls: string[]; directives: undefined[]; }' is not assignable to parameter of type 'Component'.
       Object literal may only specify known properties, and 'directives' does not exist in type 'Component'.

我的导入如下所示。

import { Component, OnInit, Input } from '@angular/core';
import { NgClass, NgStyle } from '@angular/common';
import { FileSelectDirective, FileDropDirective, FileUploadModule, FileUploader, FileUploaderOptions } from 'ng2-file-upload';

当我运行应用ng serve时，我看到控制台中报告了以下错误。

zone.js:388 Unhandled Promise rejection: Template parse errors:
Can't bind to 'uploader' since it isn't a known property of 'div'. ("
  [ngClass]="{'nv-file-over': hasBaseDropZoneOver}"
  (fileOver)="fileOverBase($event)"
  [ERROR ->][uploader]="uploader"
  class="well my-drop-zone">

这是package.json中的依赖项。

{
  "name": "app-www",
  "version": "0.0.0",
  "license": "MIT",
  "angular-cli": {},
  "scripts": {
    "start": "ng serve",
    "lint": "tslint \"src/**/*.ts\"",
    "test": "ng test",
    "pree2e": "webdriver-manager update",
    "e2e": "protractor"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "~2.1.1",
    "@angular/compiler": "~2.1.1",
    "@angular/core": "~2.1.1",
    "@angular/forms": "~2.1.1",
    "@angular/http": "~2.1.1",
    "@angular/platform-browser": "~2.1.1",
    "@angular/platform-browser-dynamic": "~2.1.1",
    "@angular/router": "~3.1.1",
    "angular2-cookie": "^1.2.5",
    "bootstrap": "^3.3.7",
    "core-js": "^2.4.1",
    "jquery": "^3.1.1",
    "lodash": "^4.16.6",
    "ng2-bootstrap": "^1.1.16",
    "ng2-file-upload": "^1.1.2",
    "rxjs": "5.0.0-beta.12",
    "ts-helpers": "^1.1.1",
    "zone.js": "^0.6.25"
  },
  "devDependencies": {
    "@types/jasmine": "^2.2.30",
    "@types/lodash": "^4.14.38",
    "@types/node": "^6.0.45",
    "angular-cli": "1.0.0-beta.19-3",
    "codelyzer": "1.0.0-beta.1",
    "jasmine-core": "2.4.1",
    "jasmine-spec-reporter": "2.5.0",
    "karma": "1.2.0",
    "karma-chrome-launcher": "^2.0.0",
    "karma-cli": "^1.0.1",
    "karma-jasmine": "^1.0.2",
    "karma-remap-istanbul": "^0.2.1",
    "protractor": "4.0.9",
    "ts-node": "1.2.1",
    "tslint": "3.13.0",
    "typescript": "~2.0.3",
    "webdriver-manager": "10.2.5"
  }
}

该文档说使用此导入语句。

import { FILE_UPLOAD_DIRECTIVES } from 'ng2-file-upload';

但在VS Code中，它说明了以下内容。

[ts] Module '"/Users/jwayne/git/app-www/node_modules/ng2-file-upload/ng2-file-upload"' has no exported member 'FILE_UPLOAD_DIRECTIVES'.

更有趣的是，我创建了自己的登录组件，如下所示。

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

为了在另一个组件中使用它，我甚至不必将它作为指令或类似的东西引用它。例如，我有一个使用此登录组件的默认组件。 HTML如下所示。

<login-component></login-component>

代码如下所示（注意组件装饰器没有指令属性）。

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

虽然现在修改了app.module.ts文件。

import { LoginComponent } from './login/login.component';
import { DefaultComponent } from './default/default.component';
@NgModule({
  declarations: [
    AppComponent,
    LoginComponent,
    DefaultComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    RouterModule.forRoot([
      { path: 'default', component: DefaultComponent },
      { path: 'main', component: MainComponent, canActivate: [ UserAuthGuard ] },
      { path: '', redirectTo: '/default', pathMatch: 'full' },
      { path: '**', redirectTo: '/default' }
    ])
  ],
  providers: [ 
    UserAuthGuard
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

所以，有很多东西正在进行，但首先，组件装饰器的指令属性发生了什么？

Answer 1

似乎文档使用的是Angular的旧版RC版本。与此同时，角度团队引入了NgModule s的概念，以更好地构建您的应用程序并避免重复使用的指令。因此，您不再声明Component装饰器中使用的指令。有关详细信息，请查看angular docs on NgModule。

您正在使用的库也适用于此，但可能文档尚未更改。检查存储库中的their demo code和this commit，了解您现在需要如何导入模块，还可以查看API更改。

Answer 2

解决此问题的关键是导入app.module.ts中的指令，然后使用@NgModule声明它们。这是app.module.ts的片段。

import { FileSelectDirective, FileDropDirective} from 'ng2-file-upload';
import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent,
    FileSelectDirective, FileDropDirective
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    RouterModule.forRoot([
      { path: 'default', component: DefaultComponent },
      { path: 'main', component: MainComponent, canActivate: [ UserAuthGuard ] },
      { path: '', redirectTo: '/default', pathMatch: 'full' },
      { path: '**', redirectTo: '/default' }
    ])
  ],
  providers: [ ... ],
  bootstrap: [AppComponent]
})
export class AppModule { }

在我的组件中，我仍然需要导入指令。这是另一个片段。

import { Component, OnInit, Input } from '@angular/core';
import { NgClass, NgStyle } from '@angular/common';
import { 
  FileSelectDirective,
  FileDropDirective, 
  FileUploader, 
  FileUploaderOptions 
} from 'ng2-file-upload';
import * as _ from 'lodash';
import { LoginService } from '../service/login.service';

@Component({
  selector: 'file-upload',
  templateUrl: './file-upload.component.html',
  styleUrls: ['./file-upload.component.css']
})
export class FileUploadComponent implements OnInit {
  //body omitted
}

Angular 2的Component装饰器中的directives属性发生了什么变化？

2 个答案: