FtpWebRequest ftpClient = (FtpWebRequest)FtpWebRequest.Create(FTPdestination+ i + ".txt");
ftpClient.Credentials = new System.Net.NetworkCredential(user, pass);
ftpClient.Method = System.Net.WebRequestMethods.Ftp.UploadFile;
ftpClient.UseBinary = true;
ftpClient.EnableSsl = true;
ftpClient.KeepAlive = true;
System.IO.FileInfo fi = new System.IO.FileInfo(server+dtm+"_"+i+".txt");
ftpClient.ContentLength = fi.Length;
byte[] buffer = new byte[4097];
int bytes = 0;
int total_bytes = (int)fi.Length;
System.IO.FileStream fs = fi.OpenRead();
System.IO.Stream rs = ftpClient.GetRequestStream();
while (total_bytes > 0)
{
    bytes = fs.Read(buffer, 0, buffer.Length);
    rs.Write(buffer, 0, bytes);
    total_bytes = total_bytes - bytes;
}
fs.Close();
rs.Close();
FtpWebResponse uploadResponse = (FtpWebResponse)ftpClient.GetResponse();
uploadResponse.Close();