BackgroundDownloader for win8.1 not working

See more:

C#

XAML

Metro-design

WinRT

, +

I have a url for a file something like "http://my.domai.com/myfile.doc" and if I open this in browser, a popup opens to enter username and password, after that I can view or download file. Now I have to do this download in my win 8.1 app. I used code below:

BackgroundDownloader backgroundDownloader = new BackgroundDownloader();
var credentials = GetNetworkCredential();
backgroundDownloader.ServerCredential = new Windows.Security.Credentials.PasswordCredential("Lighthouse", credentials.UserName, credentials.Password);
CancellationTokenSource cts = new CancellationTokenSource();

DownloadOperation downloadOperation = backgroundDownloader.CreateDownload(new Uri(System.Net.WebUtility.UrlDecode(searchDoc.Path)), fileToSave);
downloadOperation.StartAsync();

But nothing happens, no error no data. Can anyone help?