Downloading files from Dropbox using C# asp.net

Question

I want to download my files from Dropbox using dropbox.api.

My current code is

public static void download(ListBox file)
    {
        file.Items.Clear();
        using (var dbx = new DropboxClient("mytoken"))
        {
            using (var responses = dbx.Files.DownloadAsync("/pakistan.txt"))      
            {

          HttpContext.Current.Response.Clear();

          HttpContext.Current.Response.ClearHeaders();

          HttpContext.Current.Response.ClearContent();

          HttpContext.Current.Response.AddHeader("Content-Disposition", attachment; filename=" + responses.Result.Response.Name);

          HttpContext.Current.Response.AddHeader("Content-Length", responses.Result.Response.Size.ToString());

          HttpContext.Current.Response.ContentType = "text/plain";

          HttpContext.Current.Response.Flush();

          HttpContext.Current.Response.TransmitFile(responses.Result.Response.Name);

          HttpContext.Current.Response.End();
            }
        }
    }

It's downloading the file, but contents are not completely present in the file.