post 发送和接收的问题

post后，接收页面　接收到的数据为空。
发送代码如下:

string postdata = @"<?xml version ='1.0'?><LTSC_command version='1.0'><command_name>provision</command_name><command_data_block><action_id>1</action_id><service_id>1008</service_id> <uid>100008888</uid><phone_number>85188888</phone_number><agent_name> OK820C-IACJ</agent_name><data_id>2688</data_id><area_code>1</area_code></command_data_block></LTSC_command>";

byte[] requestbytes = System.Text.Encoding.Default.GetBytes(postdata);
string url = "http://125.XX.XX.XXX/wapPost/Default2.aspx";
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.Timeout = 10000000; //设定超时值
req.ContentType = "application/x-www-form-urlencoded";
req.Method = "POST";
req.ContentLength = requestbytes.Length;
Stream requeststream = req.GetRequestStream();
requeststream.Write(requestbytes, 0, requestbytes.Length);
requeststream.Close();

接收代码如下:
System.IO.StreamWriter swb = null;
        string LogPath = Server.MapPath("log.txt");
        swb = new System.IO.StreamWriter(@LogPath, true, System.Text.Encoding.Default);
        swb.WriteLine("12345");
        try
        {
            Stream resStream = Request.InputStream;
            StreamReader sr = new StreamReader(resStream, System.Text.Encoding.Default);
            //Response.Write(sr.ReadToEnd());

            // swb.Write(xmldoc.OuterXml);
            swb.WriteLine(sr.ReadToEnd());
           // swb.WriteLine("1234");
            swb.close();

}
catch
{

}

--------------------编程问答-------------------- 不得哦！没人!!!!! --------------------编程问答-------------------- 不会  顶一下 --------------------编程问答--------------------

补充：.NET技术 ,  ASP.NET