How to download data from http:\\ftp using c# .net windows service?

public static void Download(string FTPFullFileName, string DestFullFileName, string UserName, string Password)
        {
            try
            {
                DestFullFileName = DestFullFileName.Replace("/", "\\");
                int indexPart = DestFullFileName.LastIndexOf("\\");
                if (indexPart != -1)
                {
                    String DestFolder = DestFullFileName.Substring(0, indexPart + 1);

                    if (!Directory.Exists(DestFolder))
                        Directory.CreateDirectory(DestFolder);
                }
                FtpWebRequest FTP = (FtpWebRequest)FtpWebRequest.Create(FTPFullFileName);
                FTP.Method = WebRequestMethods.Ftp.DownloadFile;
                FTP.UseBinary = true;
                FTP.Proxy = null;
                FTP.Credentials = new NetworkCredential(UserName, Password);
                FtpWebResponse Response = (FtpWebResponse)FTP.GetResponse();
                Stream FtpStream = Response.GetResponseStream();
                int BufferSize =Convert.ToInt32(FileSize(FTPFullFileName, UserName, Password)) ;
                byte[] Buffer = new byte[BufferSize];
                FileStream OutputStream = new FileStream(DestFullFileName, FileMode.Create);
                int ReadCount = FtpStream.Read(Buffer, 0, BufferSize);
                while (ReadCount > 0)
                {
                    OutputStream.Write(Buffer, 0, ReadCount);
                    ReadCount = FtpStream.Read(Buffer, 0, BufferSize);
                }
                FtpStream.Close();
                OutputStream.Close();
                Response.Close();
            }
            catch (Exception ex)
            {
               // throw new Exception(ex.Message);
            }
        }

public static long FileSize(string FTPFullFileName, string UserName, string Password)
        {
            try
            {
                FtpWebRequest FTP = (FtpWebRequest)FtpWebRequest.Create(FTPFullFileName);
                FTP.Method = WebRequestMethods.Ftp.GetFileSize;
                FTP.UseBinary = true;
                FTP.Credentials = new NetworkCredential(UserName, Password);
                FtpWebResponse Response = (FtpWebResponse)FTP.GetResponse();
                Stream FtpStream = Response.GetResponseStream();
                long FileSize = Response.ContentLength;
                FtpStream.Close();
                Response.Close();
                return FileSize;
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
        }

Download(@"ftp:\\192.xxx.xx.xx\inetpub\ftproot\RetailAgreement\abc.JPG", @"E:\c.jpg", ftpUserID, ftpPassword);