Question

我可以从简单的json获取数据，但是我尝试从更复杂的（对我来说）json获取数据，并且我可以获得初始数据，但是我在获取其余数据方面遇到了麻烦。我的json（link）：

0   
table   "C"
no  "043/C/NBP/2018"
tradingDate "2018-02-28"
effectiveDate   "2018-03-01"
rates   
0   
currency    "dolar amerykański"
code    "USD"
bid 3.3875
ask 3.4559
1   
currency    "dolar australijski"
code    "AUD"
bid 2.6408
ask 2.6942
2   
currency    "dolar kanadyjski"
code    "CAD"
bid 2.6468
ask 2.7002

我可以获得像这个表，没有，tradingDate或effectiveDate这样的数据，但我不能从费率中获取数据，例如。货币，代码，出价或询问。如何从我的json获取这些数据？我的服务：

import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import "rxjs/Rx";
import {Npb} from './npb';

import { Http , Response, HttpModule} from '@angular/http';

@Injectable()
export class NbpService {

  private _postsURL = "http://api.nbp.pl/api/exchangerates/tables/c/?format=json";

  constructor(private http: Http) {
  }

  getPosts(): Observable<Npb[]> {
      return this.http
          .get(this._postsURL)
          .map((response: Response) => {
              return <Npb[]>response.json();              
          })         
  }
  private handleError(error: Response) {
      return Observable.throw(error.statusText);
  }
}

组件：

import { Component, OnInit } from '@angular/core';
import {NbpService} from './nbp.service';
import {Npb} from './npb';

@Component({
  selector: 'app-home',
  templateUrl: './home.component.html',
  styleUrls: ['./home.component.css'],
  providers: [NbpService]
})
export class HomeComponent implements OnInit {
  _postsArray: Npb[];
  constructor(private NbpService: NbpService, ) {
  }
  getPost(): void {
    this.NbpService.getPosts()
        .subscribe(
            resultArray => this._postsArray= resultArray,
            error => console.log("Error :: " + error)
        )
}

ngOnInit(): void {
    this.getPost();
}
}

和html：

 <tr *ngFor="let post of _postsArray">

    <td>USD</td>
    <td>{{post.effectiveDate}}</td>
    <td>{{post.tradingDate}}</td>
    <td>{{post.ask}}</td>
  </tr>

和Nbp：

export interface Npb {
    date: string;
    buy: string;
    sel: string;
}

Answer 1

当您订阅时收到

public class MinfyAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        var request = filterContext.HttpContext.Request;
        var response = filterContext.HttpContext.Response;

        if (!filterContext.IsChildAction) //<--you need to make sure context is not a child action
        {
            response.Filter = new Minify(response.Filter, s =>
            {
                s = Regex.Replace(s, @"\s+", " ");
                s = Regex.Replace(s, @"\s*\n\s*", "\n");
                s = Regex.Replace(s, @"\s*\>\s*\<\s*", "><");
                s = Regex.Replace(s, @"<!--(.*?)-->", "");   //Remove comments

                var firstEndBracketPosition = s.IndexOf(">");
                if (firstEndBracketPosition >= 0)
                {
                    s = s.Remove(firstEndBracketPosition, 1);
                    s = s.Insert(firstEndBracketPosition, ">");
                }
                return s;
            }); // i'm getting exception here on this code block
        }
    }
}

那是：一个元素的数组，所以

[table:..,rates:[{currency:aa,code:bb,}{{currency:aa,code:bb,}..]

和

result[0]={table:..rates:[{...},{...}]}

所以

result[0].rates={{...},{...}]

注意：使用httpClient而不是＆＃34; old＆＃34; http，请参阅https://angular.io/guide/http#httpclient

Answer 2

你不能像你一样从问中得到价值。因为ask在rates数组中。你可以做<td>{{post.rates[0].currency}}</td>，它会给你数组第一个元素的货币。

如果您想要打印所有费率，您必须再做一次循环：

<tr *ngFor='let rate of post.rates'>
  <td>{{rate.currency}}</td>
  <td>{{rate.code}}</td>
  <td>{{rate.bid}}</td>
  <td>{{rate.ask}}</td>
</tr>

angular 4从特定的json获取数据

2 个答案: