SystemTrayMenu/Helper/File/FileUrl.cs

using Microsoft.Win32;
using System;

namespace SystemTrayMenu.Helper
{
    public class FileUrl
    {
        private static string browserPath = string.Empty;
        public static string GetDefaultBrowserPath()
        {
            string urlAssociation = @"Software\Microsoft\Windows\Shell\Associations\UrlAssociations\http";
            string browserPathKey = @"$BROWSER$\shell\open\command";

            RegistryKey userChoiceKey = null;
            string browserPath = FileUrl.browserPath;

            if (string.IsNullOrEmpty(browserPath))
            {
                //Read default browser path from userChoiceLKey
                userChoiceKey = Registry.CurrentUser.OpenSubKey(urlAssociation + @"\UserChoice", false);

                //If user choice was not found, try machine default
                if (userChoiceKey == null)
                {
                    //Read default browser path from Win XP registry key
                    var browserKey = Registry.ClassesRoot.OpenSubKey(@"HTTP\shell\open\command", false);

                    //If browser path wasn’t found, try Win Vista (and newer) registry key
                    if (browserKey == null)
                    {
                        browserKey =
                        Registry.CurrentUser.OpenSubKey(
                        urlAssociation, false);
                    }
                    var path = CleanifyBrowserPath(browserKey.GetValue(null) as string);
                    browserKey.Close();
                    return path;
                }
                else
                {
                    // user defined browser choice was found
                    string progId = (userChoiceKey.GetValue("ProgId").ToString());
                    userChoiceKey.Close();

                    // now look up the path of the executable
                    string concreteBrowserKey = browserPathKey.Replace("$BROWSER$", progId);
                    var kp = Registry.ClassesRoot.OpenSubKey(concreteBrowserKey, false);
                    browserPath = CleanifyBrowserPath(kp.GetValue(null) as string);
                    kp.Close();
                }

                FileUrl.browserPath = browserPath;
            }

            return browserPath;
        }

        private static string CleanifyBrowserPath(string p)
        {
            string[] url = p.Split('"');
            string clean = url[1];
            return clean;
        }
    }
}