角2自定义服务未注入指令 [英] Angular 2 custom service not injected into a directive

问题描述

我已经app.component这样。

I have app.component like this.

import {Component} from "angular2/core"
import {HTTP_PROVIDERS} from "angular2/http"

import {ChartDataService} from '../service/chartData.service'
import {FilterService} from "../service/filter.service"

@Component({
    selector: 'app',
    template: `
        <sidebar (filterChange)="onFilterChange($event)"></sidebar>
        <div dsChart></div>
    `,
    directives: [SidebarComponent, ChartDirective],
    providers: [HTTP_PROVIDERS, FilterService, ChartDataService],
    styleUrls: ['app/main/app.component.css']
})

export class AppComponent {
     //some more code
}

chartData.service.ts：

chartData.service.ts:

import {Injectable} from 'angular2/core'
import {Http, Response, Headers, RequestOptions, RequestMethod} from 'angular2/http'

import {Url} from '../url'
import {FilterModel} from '../model/filter.model'
import {INode} from "../model/node.model"

@Injectable()
export class ChartDataService {
    constructor(private _http: Http) {
        this._headers.append('Content-Type', 'application/json');
    }    

    getData(model?: FilterModel) {
    }
}

然后我尝试使用ChartDataService里面chart.directive，这是一个子组件app.component。 chart.directive.ts：

Then I try to use ChartDataService inside chart.directive, which is a child component to app.component. chart.directive.ts:

import {Directive, ElementRef, Input, OnInit} from 'angular2/core'
import {ChartDataService} from "../service/chartdata.service"

@Directive({
    selector: '[dsChart]'
})
export class ChartDirective implements OnInit {    
    constructor(
        private el: ElementRef,
        private _dataService: ChartDataService) {
    }

    ngOnInit() {
        this._dataService.getData()
            .then(node => this._render(node))
            .catch(error => { throw error });
    }

    private _render(root: INode) {}
}

但它没有通过的文档的每个组件具有在组件级范围创建依赖注射器。如果有不使用任何适当的组件级供应商父组件的供应商。这工作正常上课与 @Component（）装饰。添加提供商：[ChartDataService] 到 @Directive 声明帮助，但是这意味着每一个装饰将有<$的单独的实例C $ C> ChartDataService 这是undesiarable。

But it fails with Via the docs each component has an injector which creates dependencies at a component level scope. If there are no any appropriate component level providers parent component's provider is used. This works fine for classes with @Component() decorator. Adding providers: [ChartDataService] to @Directive declaration helps, but that means each decorator will have separate instance of ChartDataService which is undesiarable.

任何想法？或者设计是什么呢？

Any ideas? Or is it by design?

推荐答案

这可能是一个问题与进口秩序......如果 app.component.ts 你进口 ChartDirective 在 ChartDataService 你可能会得到你所提到的错误：

This could be an issue with order of imports... If in app.component.ts you import ChartDirective before ChartDataService you might get an error you mentioned:

没有供应商ChartDataService！ （ChartDirective - > ChartDataService）

No provider for ChartDataService! (ChartDirective -> ChartDataService)

您应该导入子组件/指令导入之前使用组件本身的服务：

You should import services that child components/directives use before importing component itself:

// no error
import {ChartDataService} from '../service/chartData.service'
import {ChartDirective} from '../chart.directive'

// can cause an error
import {ChartDirective} from '../chart.directive'
import {ChartDataService} from '../service/chartData.service'

我无法在这里重现此问题： http://plnkr.co/edit/NoZJnCMlqKkOMm5erfDW ，但我可以肯定，它可以发生：

I was unable to reproduce this issue here: http://plnkr.co/edit/NoZJnCMlqKkOMm5erfDW, but I can confirm it can happen:

// routes.ts
// no error
export {SettingsRoute} from './routes/settings/settings.route'
export {RootRoute} from './routes/root/root.route'

// this causes error
// export {RootRoute} from './routes/root/root.route'
// export {SettingsRoute} from './routes/settings/settings.route'

// root.route.ts
import {SettingsRoute} from './routes'
@RouteConfig([
  { path: '/settings/...', name: 'Settings', component: SettingsRoute },
])
export class RootRoute {...}

这篇关于角2自定义服务未注入指令的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！