自动模拟页面提交操作（WebResponse）

string param="";
System.Net.HttpWebRequest req = System.Net.HttpWebRequest.Create(url) as System.Net.HttpWebRequest;
                req.Method = "POST";
                req.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; Q312461; .NET CLR 1.0.3705)";
                req.ContentType = "application/x-www-form-urlencoded";
                //
                System.Net.NetworkCredential cre=new System.Net.NetworkCredential("scott wang","xxxxx","bqc");
                System.Net.WebProxy proxy=new System.Net.WebProxy("h00proxy",80);
                proxy.BypassProxyOnLocal=true;
                proxy.Credentials=cre;
                req.Credentials = cre;
                req.Proxy=proxy;
 
                byte[] postData = System.Text.Encoding.Default.GetBytes(param);
 
                req.ContentLength = postData.Length;
                System.IO.Stream postStream = req.GetRequestStream();
                postStream.Write(postData, 0, postData.Length);
                postStream.Close();
 
                System.Net.HttpWebResponse result = req.GetResponse() as System.Net.HttpWebResponse;
                System.IO.Stream ReceiveStream = result.GetResponseStream();
 
                Byte[] read = new Byte[512];
                int bytes = ReceiveStream.Read(read, 0, 512);
                System.Text.StringBuilder pageHtml=new System.Text.StringBuilder();
                while (bytes > 0)
                ...{
 
                    System.Text.Encoding encode = System.Text.Encoding.GetEncoding("gb2312");
                    pageHtml.Append(encode.GetString(read, 0, bytes));
                    bytes = ReceiveStream.Read(read, 0, 512);
                }