C#自动登录网页浏览页面 抓取数据

http://www.cnblogs.com/netwom/articles/953430.html

        public static string PostAndGetHTML(string targetURL,CookieContainer cc, Hashtable param)

        {

            //prepare the submit data

            string formData = "";

            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 = 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;

        }

        private void button2_Click(object sender, EventArgs e)

        {

            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 = 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 = PostAndGetHTML(url2, cc, new Hashtable());

            //ConvertToDT the html or do something others

        }

这是一个简单的抓取网页数据的函数（针对Table内的，直接转化成DataTable

private 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 = "";

                    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);

                    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;