CurrencyConvertor.cs

using System.IO;
using System.Net;
using System.Text.RegularExpressions;
using ClassLibraries.SiteSettings.Classes;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;

namespace ClassLibraries.SiteSettings.Currency
{
    public static class CurrencyTool
    {
        public static bool TryGetCurrencySymbol(string ISOCurrencySymbol, out RegionInfo symbol)
        {
            symbol = CultureInfo
                .GetCultures(CultureTypes.AllCultures)
                .Where(c => !c.IsNeutralCulture)
                .Select(culture =>
                {
                    try
                    {
                        return new RegionInfo(culture.LCID);
                    }
                    catch
                    {
                        return null;
                    }
                }).FirstOrDefault(ri => ri != null && ri.ISOCurrencySymbol == ISOCurrencySymbol);
            return symbol != null;
        }

        public static string GetPriceWithCurrency(this decimal price)
        {
            SiteSetting currencySetting = null;
            currencySetting = SiteSettingDao.GetByName("Currency");
            if (currencySetting != null)
            {
                RegionInfo symbol = null;
                TryGetCurrencySymbol(currencySetting.Value, out symbol);
                if (symbol != null)
                    return String.Format("{0} {1} {2}", symbol.CurrencySymbol, price, symbol.ISOCurrencySymbol);
            }
            return String.Format("{0} {1} AUD", "$", price);
        }

        public static Currency.Classes.Currency GetCurrency()
        {
            SiteSetting currencySetting = null;
            var currency = new Classes.Currency()
            {
                Code = "$",
                Name = "AUD",
            };
            currencySetting = SiteSettingDao.GetByName("Currency");
            if (currencySetting != null)
            {
                RegionInfo symbol = null;
                TryGetCurrencySymbol(currencySetting.Value, out symbol);
                if (symbol != null)
                {
                    currency.Code = symbol.CurrencySymbol;
                    currency.Name = symbol.ISOCurrencySymbol;
                }
                return currency;
            }
            return currency;
        }

        public static decimal ConvertCurrency(string fromCurrency, string toCurrency, decimal amount)
        {
            if(amount ==0 )
                return (decimal)0.0;

            //Grab your values and build your Web Request to the API
            string apiURL = String.Format("https://www.google.com/finance/converter?a={0}&from={1}&to={2}&meta={3}", amount, fromCurrency, toCurrency, Guid.NewGuid().ToString());

            //Make your Web Request and grab the results
            var request = WebRequest.Create(apiURL);

            //Get the Response
            var streamReader = new StreamReader(request.GetResponse().GetResponseStream(), System.Text.Encoding.ASCII);

            //Grab your converted value (ie 2.45 USD)
            var result = Regex.Matches(streamReader.ReadToEnd(), "<span class=\"?bld\"?>([^<]+)</span>")[0].Groups[1].Value;
            Regex regex = new Regex(@"^-?\d+(?:\.\d+)?");
            Match match = regex.Match(result);
            if (match.Success)
            {
                return Math.Round(decimal.Parse(match.Value), 2); ;
            }
            return (decimal) 0.0;
        }
    }
}