problem with asynchronously downloading in asp.net

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.NET3.5

C#

.NET

Dear friends

I am doing task regarding file uploading and asynchronously downloading.But am getting problem in file downloading.

File getting download in specified location but its bytes not getting transfer means 0 bytes files getting me.

my code is here

FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(ConfigurationSettings.AppSettings["RemoteFileLocation"].ToString() + lblFolderName.Text);
                        ftpRequest.Credentials = new NetworkCredential(ConfigurationSettings.AppSettings["UsrNm"].ToString(), ConfigurationSettings.AppSettings["Pwd"].ToString());
                        ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                        FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
                        StreamReader streamReader = new StreamReader(response.GetResponseStream());

                        string line = streamReader.ReadLine();
                        while (!string.IsNullOrEmpty(line))
                        {

                            using (WebClient webClient = new WebClient())
                            {
                                webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(ProgressChanged);
                                webClient.DownloadFileAsync(new Uri(string.Concat(ConfigurationSettings.AppSettings["RemoteFileLocation"].ToString(), lblFolderName.Text, "/", line)), string.Concat(savePath, "/", line));
                                webClient.DownloadFileCompleted += new AsyncCompletedEventHandler(Completed);
                                btnDelete.Enabled = false;
                                btnDownload.Enabled = false;
                                button1.Enabled = false;
    
                            }
                            
                            line = streamReader.ReadLine();
                        }
                        streamReader.Close();


 private void ProgressChanged(object sender, DownloadProgressChangedEventArgs e)
        {

            try
            {
                progressBar1.Value = e.ProgressPercentage;
                if (e.ProgressPercentage == 100)
                {
                    aa = aa + 1;
                    if (aa >= 1)
                    {
                        lblStatus.Text = (aa).ToString() + " Files Downloaded";
                        if (aa == count)
                        {
                            lblStatus.Text = "Downloading Complete";
                        }
                    }

                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void Completed(object sender, AsyncCompletedEventArgs e)
        {
            

        }

please help me.