将文件从FTP下载到客户端PC

Question

在我的应用程序中，我要求客户端/用户需要将视频文件从ftp服务器下载到本地计算机。

通过使用下面的代码，我可以从ftp下载文件，但它只保存在我的应用程序服务器而不是本地客户端pc中。 我想将文件下载到客户端电脑，下载前应该询问对话框。

我的代码正在关注，

        string ResponseDescription = "";
        string PureFileName = new FileInfo(filename).Name;
        string DownloadedFilePath = @"E:\\aa\\" + PureFileName;
        String downloadUrl = String.Format("{0}/{1}", "ftp://abcd.int/", filename);
        FtpWebRequest req = (FtpWebRequest)FtpWebRequest.Create(downloadUrl);
        req.Method = WebRequestMethods.Ftp.DownloadFile;
        req.Credentials = new NetworkCredential("username", "password");
        req.UseBinary = true;
        req.Proxy = null;
            FtpWebResponse response = (FtpWebResponse)req.GetResponse();
            Stream stream = response.GetResponseStream();
            byte[] buffer = new byte[2048];
            FileStream fs = new FileStream(DownloadedFilePath, FileMode.Create);
            int ReadCount = stream.Read(buffer, 0, buffer.Length);
            while (ReadCount > 0)
            {
                fs.Write(buffer, 0, ReadCount);
                ReadCount = stream.Read(buffer, 0, buffer.Length);
            }
            ResponseDescription = response.StatusDescription;
            fs.Close();
            stream.Close();