HTTP get、post请求

Post请求：

   string postData = "user=123&pass=456"; // 要发放的数据 
   byte[] byteArray = Encoding.UTF8.GetBytes(postData);

   HttpWebRequest objWebRequest = (HttpWebRequest)WebRequest.Create("http://www.abc.com/a.aspx");
   objWebRequest.Method = "POST";
   objWebRequest.ContentType = "application/x-www-form-urlencoded";
   objWebRequest.ContentLength = byteArray.Length;
   Stream newStream = objWebRequest.GetRequestStream();
   // Send the data. 
   newStream.Write(byteArray, 0, byteArray.Length); //写入参数 
   newStream.Close();

   HttpWebResponse response = (HttpWebResponse)objWebRequest.GetResponse();
   StreamReader sr = new StreamReader(response.GetResponseStream(), Encoding.Default);
   string textResponse = sr.ReadToEnd(); // 返回的数据

接收参数：string a= Request.Form["user"];