AlticeStockChecker - Version finale

Form1.cs

using System.Drawing;
using System.Globalization;
using System.Net;
using System.Text.RegularExpressions;
using System.Windows.Forms;

namespace AlticeStockChecker
{
    public partial class Form1 : Form
    {
        float lastStock = 0.0f;

        public Form1()
        {
            InitializeComponent();
            this.Text = Application.ProductName;
            GetAndCleanStockValue();
        }

        private void GetAndCleanStockValue()
        {
            try
            {
                string webPageCode = string.Empty;

                webPageCode = GetHTMLCode("https://finance.yahoo.com/quote/ATC.AS?p=ATC.AS");
                float stock = ExtractFloatValue(webPageCode);
                UpdateLabelWithColor(stock);
            }
            catch (System.Exception)
            {
                lblStock.Text = "Erreur";
            }
        }

        private string GetHTMLCode(string url)
        {
            string webPageCode = string.Empty;

            using (WebClient wc = new WebClient())
            {
                webPageCode = wc.DownloadString(url);
            }

            return webPageCode;
        }

        private float ExtractFloatValue(string webPageCode)
        {
            string rawStock = Regex.Match(webPageCode,
                                "currentPrice\":{\"raw\":(.+?),",
                                RegexOptions.Singleline).Groups[1].Value;

            float stock = 0.0f;
            float.TryParse(rawStock,
                NumberStyles.Number,
                CultureInfo.CreateSpecificCulture("en-US"),
                out stock);
            return stock;
        }

        private void UpdateLabelWithColor(float stock)
        {
            if (stock > lastStock && lastStock != 0.0)
            {
                lblStock.ForeColor = Color.Green;
            }
            else if (stock < lastStock && lastStock != 0.0)
            {
                lblStock.ForeColor = Color.Red;
            }
            else
            {
                lblStock.ForeColor = Color.Black;
            }

            lastStock = stock;

            string finalStock = string.Format("{0} euros", stock.ToString());
            lblStock.Text = finalStock;
        }

        private void timer1_Tick(object sender, System.EventArgs e)
        {
            GetAndCleanStockValue();
        }
    }
}