/// <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 = "";
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;
}