FileInfo fiLocalFile = new FileInfo(sSrcFileName);
ftpWebReq = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + sServerIP + "/" + sDstFileName));
ftpWebReq.Credentials = new NetworkCredential(sUserID, sPassword);
               
ftpWebReq.UsePassive = false; 
ftpWebReq.KeepAlive = false;
ftpWebReq.Method = WebRequestMethods.Ftp.UploadFile;
ftpWebReq.UseBinary = true;
ftpWebReq.ContentLength = fiLocalFile.Length;
MessageBox.Show(ftpWebReq.ToString());
int iBuffLen = 2048;
byte[] baBuff = new byte[iBuffLen];
int iConLen;

FileStream fsLocalFile = fiLocalFile.Open(FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
Stream stmReq = ftpWebReq.GetRequestStream();
iConLen = fsLocalFile.Read(baBuff, 0, iBuffLen);
while (iConLen != 0)
{
    stmReq.Write(baBuff, 0, iConLen);
    iConLen = fsLocalFile.Read(baBuff, 0, iBuffLen);
}

stmReq.Close();
fsLocalFile.Close();