/// <summary>        /// visit the target url        /// </summary>        /// <param name="targetURL"></param>        /// <param name="cc">this is for keeping cookies and sessions</param>        /// <param name="param">this is the data need post inside form</param>        /// <returns>html page</returns>        public static string PostAndGetHTML(string targetURL,CookieContainer cc,Hashtable param)        {            //prepare the submit data            string formData = http://www.mamicode.com/"";            foreach (DictionaryEntry de in param)            {                formData += de.Key.ToString() + "=" + de.Value.ToString() + "&";            }            if (formData.Length > 0)                formData = formData.Substring(0, formData.Length - 1); //remove last ‘&‘            ASCIIEncoding encoding = new ASCIIEncoding();            byte[] data =http://www.mamicode.com/ encoding.GetBytes(formData);            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(targetURL);            request.Method = "POST";    //post            request.ContentType = "application/x-www-form-urlencoded";            request.ContentLength = data.Length;            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; SV1; .NET CLR 2.0.1124)";            Stream newStream = request.GetRequestStream();            newStream.Write(data, 0, data.Length);            newStream.Close();            request.CookieContainer = cc;            HttpWebResponse response = (HttpWebResponse)request.GetResponse();            cc.Add(response.Cookies);            Stream stream = response.GetResponseStream();            string result = new StreamReader(stream, System.Text.Encoding.Default).ReadToEnd();            return result;        }        public static DataTable ConvertToDT(DataTable dt, string tableHTML)        {            int lastTD = tableHTML.ToLower().LastIndexOf("</td>");            int firstRow = tableHTML.ToLower().IndexOf("<tr") + 3;//after ""<tr            int index = tableHTML.ToLower().IndexOf("<tr", firstRow) + 3;//after ""<tr            while (index < lastTD)            {                DataRow dr = dt.NewRow();                for (int i = 0; i < dt.Columns.Count; i++)                {                    string value = http://www.mamicode.com/"";                    int startTD = tableHTML.ToLower().IndexOf("<td", index) + 3;//after "<td"                    int endTD = tableHTML.ToLower().IndexOf("</td>", startTD);                    if (endTD < 0)                        break;                    string tdStr = tableHTML.Substring(startTD, endTD - startTD);                    //remove <> and others                    tdStr = tdStr.Replace("&nbsp;", "").Replace("\t", "").Replace("\r", "");                    string[] v = tdStr.Split(‘<‘, ‘>‘);                    for (int j = 0; j < v.Length; j++)                    {                        j++;                        if (v[j].Trim() != "")                        {                            value = v[j].Trim();                            break;                        }                    }                    //                    dr[i] = value;                    index = endTD;                }                dt.Rows.Add(dr);            }            return dt;        }

CookieContainer cc = new CookieContainer();//this is for keep the Session and Cookie            Hashtable param = new Hashtable();//this is for keep post data.            string urlLogin = "http://demo.server//login.asp";            //do find the elementId that needed. check the source of login page can get this information            param.Add("User", "xxx");            param.Add("Password", "xxxx");            string result =GrabHelper.PostAndGetHTML(urlLogin, cc, param);            //check result, whether login success            //if login success, goto the target url, and input some value.            string url2 = " http://demo.server/query.asp?id=1";// need change. special logic            param.Clear();            //param.Add("SearchAreaId","JobId")            result = GrabHelper.PostAndGetHTML(url2, cc, new Hashtable());            //ConvertToDT the html or do something others