C#模拟登录总结

/// <summary>  登录
        /// </summary>
        /// <param name="url"></param>
        /// <param name="paramList"></param>
        /// <returns></returns>
        public static string Login(String url, String paramList)
        {
            HttpWebResponse res = null;
            string strResult = "";
            try
            {
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
                req.Method = "POST";
                req.ContentType = "application/x-www-form-urlencoded";
                req.AllowAutoRedirect = false;
                CookieContainer cookieCon = new CookieContainer();
                req.CookieContainer = cookieCon;
                StringBuilder UrlEncoded = new StringBuilder();
                Char[] reserved = { '?', '=', '&' };
                byte[] SomeBytes = null;
                if (paramList != null)
                {
                    int i = 0, j;
                    while (i < paramList.Length)
                    {
                        j = paramList.IndexOfAny(reserved, i);
                        if (j == -1)
                        {
                            UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length - i)));
                            break;
                        }
                        UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j - i)));
                        UrlEncoded.Append(paramList.Substring(j, 1));
                        i = j + 1;
                    }
                    SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString());
                    req.ContentLength = SomeBytes.Length;
                    Stream newStream = req.GetRequestStream();
                    newStream.Write(SomeBytes, 0, SomeBytes.Length);
                    newStream.Close();
                }
                else
                {
                    req.ContentLength = 0;
                }

                res = (HttpWebResponse)req.GetResponse();
                cookieheader = req.CookieContainer.GetCookieHeader(new Uri(url));
                Stream ReceiveStream = res.GetResponseStream();
                Encoding encode = System.Text.Encoding.GetEncoding("GBK");
                StreamReader sr = new StreamReader(ReceiveStream, encode);
                Char[] read = new Char[256];
                int count = sr.Read(read, 0, 256);
                while (count > 0)
                {
                    String str = new String(read, 0, count);
                    strResult += str;
                    count = sr.Read(read, 0, 256);
                }
            }
            catch (Exception e)
            {
                strResult = e.ToString();
            }
            finally
            {
                if (res != null)
                {
                    res.Close();
                }
            }
            return strResult;
        }
        /// <summary>  获取页面HTML
        /// </summary>
        /// <param name="url"></param>
        /// <param name="paramList"></param>
        /// <returns></returns>
        public static string getPage(String url, String paramList)
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            req.Headers["If-None-Match"] = "36d0ed736e88c71:d9f";
            req.Referer = "http://website/login.do";
            CookieContainer cookieCon = new CookieContainer();
            req.CookieContainer = cookieCon;
            req.CookieContainer.SetCookies(new Uri(url), cookieheader);
            HttpWebResponse res = (HttpWebResponse)req.GetResponse();
            StreamReader sr = new StreamReader(res.GetResponseStream(),Encoding.Default);
            string strResult = sr.ReadToEnd();
            sr.Close();
            return strResult;
        }调用:

        string postData = "userName=admin&password=pass&area=2006&Submit=%B5%C7+%C2%BC";           
        string strLogin, strResult;
        strLogin = Login("http://website/login.do", postData);

         strResult = getPage("http://website/tohjtree.do", "");
//输出
         this.webBrowser1.Document.Write(strResult);