ajax 上传 demo

string result = "N";
        if (Request.QueryString["FILENAME"] != null)
        {
            try
            {
                string fileName = Server.UrlDecode(Request.QueryString["FILENAME"]).Substring(Request.QueryString["FILENAME"].LastIndexOf("."));

                StringBuilder newFileName = new StringBuilder(DateTime.Now.ToString("yyyyMMddhhss")).Append(fileName);

                WebClient webClient = new WebClient();

                webClient.Credentials = CredentialCache.DefaultCredentials;

                FileStream fs = new FileStream(Server.UrlDecode(Request.QueryString["FILENAME"]), FileMode.Open, FileAccess.Read);

                BinaryReader br = new BinaryReader(fs);

                byte[] postArray = br.ReadBytes(Convert.ToInt32(fs.Length));

                string temp = Server.MapPath(@"~/images/") + newFileName;
                Stream postStream = webClient.OpenWrite(temp, "PUT");


                if (postStream.CanWrite)
                {
                    postStream.Write(postArray, 0, postArray.Length);
                    result = "Y";
                }
            }
            catch
            {
            }
            finally
            {
                Response.Write(result);
            }