为什么程序不将格里夫纳汇率转换为欧元？

VasoKri 发表于 Dev

瓦索克里

编写一个将格里夫纳汇率转换为$，Euro的程序。

一天中的好时光。我试图编写一个程序，使用官方网站上的当前汇率。请更正我的错误，并添加我做错的评论。谢谢你。

using System;
using System.Net;


namespace Currency_Converter
{
class Program
{
    static void Main()
    {
        Console.Write("Enter the amount of hryvnia: ");
        double uah = double.Parse(Console.ReadLine());
        double cource = GetCourse();
        Console.WriteLine("Euro exchange rate: " + cource);
        Console.WriteLine("{0} UAH. = {1} Euro.", uah, 
            Math.Round(uah / GetCourse(), 2));
        Console.ReadKey();
    }
    static double GetCourse()
    {
        WebClient client = new WebClient();
        client.Encoding = System.Text.Encoding.UTF8;
        string data = 
client.DownloadString("https://bank.gov.ua/ua/markets/exchangerates? 
date=20.02.2021&period=daily");
        string ff = data.Substring(data.IndexOf("<td>33,6478</td>"));
        ff = ff.Substring(ff.IndexOf("<td>") + 4);
        ff = ff.Remove(ff.IndexOf("</td>")).Replace('.', ',');
        return double.Parse(ff);
    }
}
}

鲍里斯·索科洛夫（Boris Sokolov）

您不应该使用网络拥挤，因为有官方的API：

using Newtonsoft.Json;
using System;
using System.Linq;
using System.Net;

namespace ConsoleApp2
{
    class Program
    {
        static void Main()
        {
            Console.Write("Enter the amount of hryvnia: ");
            double uah = double.Parse(Console.ReadLine());
            double cource = GetCourse();
            Console.WriteLine("Euro exchange rate: " + cource);
            Console.WriteLine("{0} UAH. = {1} Euro.", uah,
                Math.Round(uah / cource, 2));
            Console.ReadKey();
        }
        static double GetCourse()
        {
            WebClient client = new WebClient();
            client.Encoding = System.Text.Encoding.UTF8;
            string data = client.DownloadString("https://bank.gov.ua/NBUStatService/v1/statdirectory/exchange?json");
            var currencies = JsonConvert.DeserializeObject<Root[]>(data);
            return currencies.Where(c => c.cc.Equals("EUR", StringComparison.InvariantCultureIgnoreCase)).First().rate;
        }
    }

    public class Root
    {
        public int r030 { get; set; }
        public string txt { get; set; }
        public double rate { get; set; }
        public string cc { get; set; }
        public string exchangedate { get; set; }
    }
}

UPD。推荐使用HttpClient。我更喜欢Newtonsoft.Json，但是您可以使用任何其他库，例如System.Text.Json

using Newtonsoft.Json;
using System;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    class Program
    {
        static void Main()
        {
            Console.Write("Enter the amount of hryvnia: ");
            double uah = double.Parse(Console.ReadLine());
            double cource = GetCourse();
            Console.WriteLine("Euro exchange rate: " + cource);
            Console.WriteLine("{0} UAH. = {1} Euro.", uah,
                Math.Round(uah / cource, 2));
            Console.ReadKey();
        }

        static double GetCourse()
        {
            Task<double> task = Task.Run(async () => await GetCourseAsync());
            return task.Result;
        }

        static async Task<double> GetCourseAsync()
        {
            var client = new HttpClient();
            HttpResponseMessage response = await client.GetAsync("https://bank.gov.ua/NBUStatService/v1/statdirectory/exchange?json");
            response.EnsureSuccessStatusCode();
            string data = await response.Content.ReadAsStringAsync();
            var currencies = JsonConvert.DeserializeObject<Root[]>(data);
            return currencies.Where(c => c.cc.Equals("EUR", StringComparison.InvariantCultureIgnoreCase)).First().rate;
        }
    }

    public class Root
    {
        public int r030 { get; set; }
        public string txt { get; set; }
        public double rate { get; set; }
        public string cc { get; set; }
        public string exchangedate { get; set; }
    }
}