我的代码如下:
private void Init(string _url)
        {            try
            {
                m_uri = new Uri(_url);
                m_links = new List<Link>();
                m_html = "";
                m_outstr = "";
                m_title = "";
                m_good = true;
                if (_url.EndsWith(".rar") || _url.EndsWith(".dat") || _url.EndsWith(".msi"))
                {
                    m_good = false;
                    return;
                }
                HttpWebRequest rqst = (HttpWebRequest)WebRequest.Create(m_uri);
                rqst.AllowAutoRedirect = true;
                rqst.MaximumAutomaticRedirections = 3;
                rqst.UserAgent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";
                rqst.KeepAlive = true;
                rqst.Timeout = 30000;
                lock (WebPage.webcookies)
                {
                    if (WebPage.webcookies.ContainsKey(m_uri.Host))
                        rqst.CookieContainer = WebPage.webcookies[m_uri.Host];
                    else
                    {
                        CookieContainer cc = new CookieContainer();
                        WebPage.webcookies[m_uri.Host] = cc;
                        rqst.CookieContainer = cc;
                    }
                }                HttpWebResponse rsps = (HttpWebResponse)rqst.GetResponse();                Stream sm = rsps.GetResponseStream();
                if (!rsps.ContentType.ToLower().StartsWith("text/") || rsps.ContentLength > 1 << 22)
                {
                    rsps.Close();
                    m_good = false;
                    return;
                }
                Encoding cding = System.Text.Encoding.Default;
                string contenttype = rsps.ContentType.ToLower();
                int ix = contenttype.IndexOf("charset=");
                if (ix != -1)
                {                    try
                    {
                        cding = System.Text.Encoding.GetEncoding(rsps.ContentType.Substring(ix + "charset".Length + 1));
                    }
                    catch
                    {
                        cding = Encoding.Default;
                    }
                    m_html = new StreamReader(sm, cding).ReadToEnd();
                }
                else
                {
                    m_html = new StreamReader(sm, cding).ReadToEnd();
                    Regex regex = new Regex("charset=(?<cding>[^=]+)?\"", RegexOptions.IgnoreCase);
                    string strcding = regex.Match(m_html).Groups["cding"].Value;
                    try
                    {
                        cding = Encoding.GetEncoding(strcding);
                    }
                    catch
                    {
                        cding = Encoding.Default;
                    }
                    byte[] bytes = Encoding.Default.GetBytes(m_html.ToCharArray());
                    m_html = cding.GetString(bytes);
                    if (m_html.Split('?').Length > 100)
                    {
                        m_html = Encoding.Default.GetString(bytes);
                    }
                }
                m_pagesize = m_html.Length;
                m_uri = rsps.ResponseUri;
                rsps.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message + m_uri.ToString());
                m_good = false;            }
        }
请问我如何才能判断Internet访问正确。网络是否畅通。如果不通。那我就得让程序一直试探。直到能重新连上网络。才继续执行下面的代码。请问如何判断。