ng2-translate在延迟加载的模块中不起作用

Question

在我正在创建的Angular 2 RC5应用程序中，我正在使用ng2-translate进行语言处理。这个应用程序有两个功能模块，一个是延迟加载的，另一个是急切加载的。TranslateModule是通过一个共享模块提供的。问题是，转换管道在急切加载的模块中工作得很好，但在延迟加载的模块中就不行了。为了验证它是否与加载方法有关，我将两者都转换为急切加载，一切都很好。

可以在这里找到一个演示该问题的废话：Plunker，重要的代码也在下面。

初始页面是急切加载的页面，因此字符串看起来很好。单击Login，它将转到延迟加载的字符串，其中所有字符串都是大写的，即不翻译。

任何帮助都将不胜感激。

app.module：

import { NgModule }      from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { TranslateModule } from 'ng2-translate/ng2-translate';
import { AppComponent }  from './app.component';
import { WelcomeModule } from './welcome/welcome.module';
import { routing }       from './app.routing';

@NgModule({
  imports: [ BrowserModule, WelcomeModule, TranslateModule.forRoot(), routing ],
  declarations: [ AppComponent ],
  bootstrap: [ AppComponent ]
})
export class AppModule { }

app.routing：

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

export const routes: Routes = [
  { path: '', redirectTo: 'welcome', pathMatch: 'full'},
  { path: 'backend', loadChildren: 'app/backend/backend.module' }
];

export const routing = RouterModule.forRoot(routes);

app.component：

import { Component } from '@angular/core';
import { TranslateService } from 'ng2-translate/ng2-translate';

@Component({
    selector: 'my-app',
    template: `
        <router-outlet></router-outlet>
    `
})
export class AppComponent { 
    constructor(translate: TranslateService) {
        // this language will be used as a fallback when a translation isn't found in the current language
        translate.setDefaultLang('en');

        // the lang to use, if the lang isn't available, it will use the current loader to get them
        translate.use('en');
    }
}

shared.module：

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { HttpModule } from '@angular/http';
import { TranslateModule } from 'ng2-translate/ng2-translate';

@NgModule({
    imports: [
        CommonModule,
        HttpModule,
        TranslateModule.forRoot()
    ],
    exports: [
        CommonModule,
        TranslateModule
    ],

})
export class SharedModule {}

welcome.module (自动加载)

import { NgModule }      from '@angular/core';
import { SharedModule } from '../shared/shared.module';
import { WelcomeComponent }  from './welcome.component';
import { routing } from './welcome.routing';

@NgModule({
  imports: [ SharedModule, routing ],
  declarations: [ WelcomeComponent ]
})
export class WelcomeModule { }

welcome.component：

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

@Component({
    template: `
        <h2>{{ 'PLEASELOGIN' | translate }}</h2>
        <nav><a routerLink="/backend">{{ 'LOGIN' | translate }}</a></nav>
    `
})
export class WelcomeComponent { }

welcome.routing

import { RouterModule }  from '@angular/router';

import { WelcomeComponent } from './welcome.component';

export const routing = RouterModule.forChild([
    { path: 'welcome', component: WelcomeComponent}
]);

backend.module (延迟加载)

import { NgModule } from '@angular/core';
import { SharedModule } from '../shared/shared.module';
import { BackendComponent } from './backend.component';
import { routing } from './backend.routing';

@NgModule({
    imports: [ SharedModule, routing ],
    declarations: [ BackendComponent ]
})
export default class BackendModule { }

backend.component：

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

@Component({
    template: `
        <h2>{{ 'WELCOME' | translate }}</h2>
        <nav><a routerLink="/welcome">{{ 'LOGOUT' | translate }}</a></nav>
    `
})
export class BackendComponent { }

backend.routing

import { Routes, RouterModule }  from '@angular/router';
import { BackendComponent }    from './backend.component';

const routes: Routes = [
    { path: '', component: BackendComponent }
];

export const routing = RouterModule.forChild(routes);

en.json

{
    "LOGIN": "Login",
    "LOGOUT": "Logout",
    "WELCOME": "Welcome!",
    "PLEASELOGIN": "Please Login"
}

Answer 1

我也有同样的问题。在forRoot方法中加入TranslateLoader和TranslateService解决了这一问题。

    import {TranslateModule, TranslateService, TranslateLoader, TranslateStaticLoader} from 'ng2-translate/ng2-translate';
    @NgModule({
        imports: [..,TranslateModule],
        declarations: [..],
        exports: [ .., TranslateModule]
    })
    export class SharedModule {

    static forRoot(): ModuleWithProviders {

       function translateLoader(http: Http) {
            return new TranslateStaticLoader(http, 'i18n', '.json');
        }
        return {
            ngModule: SharedModule,
            providers: [UserService, ItemService, {
                provide: TranslateLoader,
                useFactory: translateLoader,
                deps: [Http]
            },
                TranslateService],
        };
    }
    }

Answer 2

尽管被接受的答案给我指明了正确的方向，但翻译器并没有在延迟加载的模块中工作。在其他模块中，它是有效的。

我必须像在app.component.ts中一样，在延迟加载的模块的主组件中再次注入TranslatorService，并初始化语言设置

export class MainComponentOfLazyLoadedModule implements OnInit {

    constructor(private translate: TranslateService) {
        Language.currentLang = "en";
        translate.addLangs(["en", "sp"]);
        translate.setDefaultLang(Language.currentLang);
        translate.use(Language.currentLang);
    }

    ngOnInit() {

    }

}