C# - URL auslesen

private void ReadURLs(string filename)
        {
            TextReader tr = new StreamReader(filename);
            string result = tr.ReadLine();
            while ((result != null) && (result != "[InternetShortcut]"))
            {
                result = tr.ReadLine();
            }
            if (result != null)
            {
                result = tr.ReadLine();
            }
            if (result != null)
            {
                result = result.Replace("URL=", "");
                tr.Close();
                tr.Dispose();
                this.webBrowser1.Navigate(result.ToString());
            }
        }