public static string HttpPost(string strUrl, NameValueCollection pars, int timeout, string charset)
{
Encoding encoding = Encoding.GetEncoding(charset);
string strPars = GetParsString(pars);
byte[] data = encoding.GetBytes(strPars);
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(strUrl);
request.Method = "POST";
request.Timeout = timeout;
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = data.Length;
Stream newStream = request.GetRequestStream();
newStream.Write(data, 0, data.Length);
newStream.Close();
string result = string.Empty;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream s = response.GetResponseStream();
StreamReader sr = new StreamReader(s, encoding);
result = sr.ReadToEnd();
sr.Close();
response.Close();
return result;
}