问题描述

我正在尝试从此URL获取实时货币汇率： http://www.webservicex.net/CurrencyConvertor.asmx/ConversionRate?FromCurrency=GBP&ToCurrency=LTL

这是我尝试的内容：

public void getRate(string howmuch, string from, string to)
    {
        int hmuch = int.Parse(howmuch);
        string url = "http://www.webservicex.net/CurrencyConvertor.asmx/ConversionRate?FromCurrency=GBP&ToCurrency=LTL";
        var xml = XDocument.Load(url);
        var result = xml.Descendants("double");
        btn.Content = result;
    }

推荐答案

在大约4小时后找到解决方案：

这是我调用函数并转换结果的方式：

double rate = await getRate("GBP", "LTL");
string res = System.Convert.ToString(rate);
output.Text = res;

请注意，必须将从中调用此函数的方法声明为函数本身，否则不能使用aWait运算符。

功能：

public async Task<double> getRate(string from, string to)
        {
            string xml = string.Empty;
            Uri url = new Uri("http://www.webservicex.net/CurrencyConvertor.asmx/ConversionRate?FromCurrency="+from+"&ToCurrency="+to);
            HttpClient httpClient = new HttpClient();
            httpClient.DefaultRequestHeaders.TryAddWithoutValidation("Accept", "text/html,application/xhtml+xml,application/xml");
            var response = await httpClient.GetAsync(url);
            using (var responseStream = await response.Content.ReadAsStreamAsync())
            using (var streamReader = new StreamReader(responseStream))
            {
               xml = streamReader.ReadToEnd();
            }
            XDocument xDoc = XDocument.Parse(xml);
            XNamespace xmlns = "http://www.webserviceX.NET/";
            string value = (string)xDoc.Element(xmlns + "double");
            return System.Convert.ToDouble(value);
        }

也不要忘记包括所需的标题：

using System.Net;
using System.Xml;
using System.Xml.Linq;
using System.Net.Http;
using System.Threading.Tasks;

这篇关于Windows Phone使用XML代码从URL获取值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！