angularjs – Angular 2：不是一个函数,但它存在

courses.component.ts：

import {Component} from 'angular2/core'
import {CourseService} from './course.service'

@Component({
    selector: 'courses',template: `
        <h2>Courses</h2>
        {{ title }}
        <ul>
            <li *ngFor ="#course of courses">
            {{course}}
            </li>
        </ul>
        `,providers: [CourseService]
})
export class CoursesComponent{
    title = "The title of courses page";
    courses;

    constructor(courseService: CourseService){
        this.courses = CourseService.getCourses();
    }
}

course.service.ts：

export class CourseService{
    getCourses() : string[]{
        return ["Course1","Course2","Course3"];
    }
}