求短网址计算~

        private static string GetShortenUrl(string longUrl)

        {

            const string urlformatter = "http://api.bit.ly/v3/shorten?login=stonepeter&apiKey=R_602a98ce2ef8feed660747065c1d7bae&longUrl={0}&format=xml";

            var bitlyRequest = string.Format(urlformatter, UrlEncode(longUrl));

            var xmlresult = WebRequest(Method.GET, bitlyRequest, null);

            var xml = new XmlDocument();

            xml.LoadXml(xmlresult);

            string shortenUrl = xml.GetElementsByTagName("url")[0].InnerText;



            return shortenUrl;

        }



        /// <summary>

        /// Replace all Urls with shorten one

        /// </summary>

        /// <param name="orginal">The orginal text string</param>

        /// <returns>If there are urls replace it with bit.ly shorten name</returns>

        public static string ReplaceUrlWithShorten(string orginal)

        {

            Regex urlRegex = new Regex(@"http://[^\s]*");

            MatchCollection matches = urlRegex.Matches(orginal);

            string result = orginal;

            

            foreach (Match match in matches)

            {

                string matchvalue = match.Value;

                result = result.Replace(matchvalue, GetShortenUrl(matchvalue));

            }

            return result;

        }