下面的代码可以post任何类型文件，主要是把数据流统一转换为base64格式.//------------------------------发送部分--------------------------------------------------string url = "http://localhost/im/upfile?aa=5";//发送到的页面的地址HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);//读取一个图片FileStream fs = new FileStream(Server.MapPath("~/NET基础知识.doc"), System.IO.FileMode.Open,     System.IO.FileAccess.Read);byte[] filecontent = new byte[fs.Length];fs.Read(filecontent, 0, filecontent.Length);fs.Close();fs.Dispose();//将图片转换成base64编码的流string a = Convert.ToBase64String(filecontent);       //读取base64编码流，发送byte[] requestBytes = System.Text.Encoding.Default.GetBytes(a);req.Method = "POST";req.ContentType = "application/x-www-form-urlencoded";req.ContentLength = requestBytes.Length;Stream requestStream = req.GetRequestStream();requestStream.Write(requestBytes, 0, requestBytes.Length);requestStream.Close();//接收返回参数，到string backstrHttpWebResponse res = (HttpWebResponse)req.GetResponse();StreamReader sr = new StreamReader(res.GetResponseStream(), System.Text.Encoding.Default);string backstr = sr.ReadToEnd();sr.Close();res.Close();//输出参数Response.Write(backstr);//-----------------------------------------------接收部分-----------------------------------//接收到的参数string bb= Request.QueryString["aa"];Encoding myEncoding = Encoding.GetEncoding("utf-8");//接收传递过来的数据流Stream resStream = Request.InputStream;byte[] filecontent = new byte[resStream.Length];//将数据流读入byte数组resStream.Read(filecontent, 0, filecontent.Length);//数组转换为string以便转换base64使用string a = myEncoding.GetString(filecontent);//将string读取base64解密到byte数组byte[] filecontent2 = Convert.FromBase64String(a);//写入目录File.WriteAllBytes(Server.MapPath("~/"+bb+".doc"), filecontent2);//返回值Response.Write("ok");Response.End();