Http Api呼叫承诺的响应未定义-Angular 2 [英] Response of Http Api call promise is undefined - Angular 2

问题描述

我已经在WebAPI中创建了一个api，如下所示.

I have created an api in WebAPI as below.

public HttpResponseMessage Get() {

            var response = Request.CreateResponse(HttpStatusCode.OK);
            response.Content = new StringContent(JsonConvert.SerializeObject("Hello World"), Encoding.UTF8, "application/json");
            return response;
        }

我正试图从Angular如下调用它

I am trying to call it from Angular as below

Service.ts

@Injectable()
export class DemoService {

     constructor(private http:Http){}

     GetHttpData(){

        return this.http.get('http://localhost:54037/api/home')
        .map((res:Response)=>res.json());
     }

组件:

export class AppComponent implements OnInit  { 

  data2: String;
  constructor(private s: DemoService){} 

  ngOnInit(){

    this.s.GetHttpData().subscribe(data=>this.data2=data);
    console.log("Http call  completed: "+this.data2);

}

在运行该应用程序时，我得到输出:

Http调用已完成:未定义

Http call completed: undefined

有人可以帮忙吗?

谢谢

推荐答案

将console.log放入数据函数中.

您可以这样尝试吗?

export class AppComponent implements OnInit  { 

  data2: String;
  constructor(private s: DemoService){} 

  ngOnInit(){

    this.s.GetHttpData().subscribe(data=>{
        this.data2=data;
        console.log("Http call  completed: "+this.data2)
    });

}

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