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[英]ERROR in : Can't resolve all parameters for MenuController in Angular6
[英]How to resolve Can't resolve all parameters error on angular
剛剛開始使用角度2,並遇到我的第一個錯誤。 我正在嘗試創建一個從服務器獲取數據的服務,但我收到此錯誤
錯誤:無法解析CourseService的所有參數:(?)。 在SyntaxError.ZoneAwareError(http:......}
這是拋出錯誤app / courses / courses.service.ts的服務代碼
import { Http } from '@angular/http';
export class CourseService {
private _courses : Object[];
public get courses() : Object[] {
return this._courses;
}
public set courses(v : Object[]) {
this._courses = v;
}
constructor(private http: Http) {
http.get("https://jsonplaceholder.typicode.com/posts").subscribe(data => {
this._courses = data.json();
});
}
}
該服務應該在app / courses / courses.component.ts中使用
import { Component } from '@angular/core'
import { CourseService } from "app/courses/course.service";
@Component({
selector: 'courses',
providers: [CourseService],
templateUrl: './courses.component.html',
styleUrls: ['./courses.component.css']
})
export class CoursesComponent {
title : string = "The title of the Course";
courses : Object[];
constructor(private courseService: CourseService) {
console.log("hello");
this.courses = courseService.courses;
}
}
和app.module包含
....
....
import { AppComponent } from './app.component';
import { CoursesComponent } from './courses/courses.component';
import { CourseService } from "./courses/course.service";
@NgModule({
declarations: [
AppComponent,
CoursesComponent,
],
imports: [
BrowserModule,
FormsModule,
HttpModule
],
providers: [CourseService],
bootstrap: [AppComponent, CoursesComponent]
})
export class AppModule { }
在導出類之前放置@Injectable()。
@Injectable()讓Angular知道一個類可以與依賴注入器一起使用。
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