string url = "http://localhost:/Activex/Serverpage.aspx";
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            string Data = "Data=测试数据";
            byte[] b = System.Text.Encoding.Default.GetBytes(Data);
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";

            request.ContentLength = b.Length;
            Stream sw = request.GetRequestStream();
            sw.Write(b, 0, b.Length); //写入数据   
            sw.Close();

            try
            {
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream sw1 = response.GetResponseStream();
                StreamReader sr = new StreamReader(sw1, System.Text.Encoding.Default);


                MessageBox.Show(sr.ReadToEnd()); //在这里输入发送后,页面返回的结果   
                sr.Close();
            }
            catch (System.Net.WebException ex)
            {
                MessageBox.Show(ex.Status.ToString());
            }