async Task<StorageFile> DownloadFileAsync(File file)
{
StorageFolder temporaryFolder = ApplicationData.Current.TemporaryFolder;
StorageFile invoice =
await temporaryFolder.CreateFileAsync(file.Name,
Windows.Storage.CreationCollisionOption.ReplaceExisting);
var stream = await file.DownloadAsync();
using (var reader = new DataReader(stream.AsInputStream()))
{
await reader.LoadAsync((uint)stream.Length);
var buffer = new byte[(int)stream.Length];
reader.ReadBytes(buffer);
await FileIO.WriteBytesAsync(invoice, buffer);
}
return invoice;
}