private async void PrintWithoutPdfViewButton_Click(object sender, RoutedEventArgs e)
{
var file = await StorageFile.GetFileFromApplicationUriAsync(new Uri ("ms-appx:///Assets/pdfs/PSPDFKit.pdf"));
var documentSource = DocumentSource.CreateFromStorageFile(file);
var printHelper = await PrintHelper.CreatePrintHelperFromSourceAsync(documentSource, this, "PrintCanvas", "PrintWithoutUI");
await printHelper.ShowPrintUIAsync();
}