Angular 2 observable-subscribe显示未定义

Question

我有同样的挑战是在SO后的面孔在这里,我的订阅方法越来越不确定我component.ts,即使在我的服务,我有数据.请参阅p.component.ts下面的代码

 private getPayItems():void{
    console.log('In getPayItems');
    this._payItemService.getPayItems()
    .subscribe(data => { 
        this.payItemArray = data;
        console.log(data);
    },
    (error:any) =>{
         this.alerts.push({ msg: error, type: 'danger', closable: true }); 
    }) 
}

p.service.ts

getPayItems():Observable<Payitem[]>{

    let  actionUrl = this.url +  "/GetPayItem";

    return this._http.get(actionUrl, { headers: this.headers })
        .map((response: Response) => { 
            <Payitem[]>response.json() ;
             console.log(<Payitem[]>response.json()); //This logs the Object
        })
        .catch(this.handleError);
}

Answer 1

正如你所使用{}它需要明确的回报function.所以你必须<Payitem[]>response.json()从map功能返回.

getPayItems():Observable<Payitem[]>{

    let  actionUrl = this.url +  "/GetPayItem";

    return this._http.get(actionUrl, { headers: this.headers })
        .map((response: Response) => { 
             console.log(<Payitem[]>response.json()); //This logs the Object
            return <Payitem[]>response.json() ;
        })
        .catch(this.handleError);
}

否则以下将是速记语法

getPayItems():Observable<Payitem[]>{
    let  actionUrl = `${this.url}/GetPayItem`;
    return this._http.get(actionUrl, { headers: this.headers })
        .map((response: Response) => <Payitem[]>response.json())
        .catch(this.handleError);
}