private async void buttonRemove_Click(object sender, RoutedEventArgs e)
        {
            BulletinFile bf = (BulletinFile)listView1.SelectedItem;

            if (bf != null)
            {
                StorageFile sf = await StorageFile.GetFileFromApplicationUriAsync(new Uri(bf.FileNameOnly));

                await sf.DeleteAsync();

                listView1.ItemsSource = null;
                listView1.ItemsSource = BulletinFileManager.GetBulletinFilesFromStorePath();
            }
        }
        private async void listView1_SelectionChangedAsync(object sender, SelectionChangedEventArgs e)
        {
            BulletinFile bf = (BulletinFile)listView1.SelectedItem;

            if (bf != null)
            {
                storageFile = await StorageFile.GetFileFromApplicationUriAsync(new Uri(bf.FileNameOnly));

                pdfDoc = await PdfDocument.LoadFromFileAsync(storageFile);

                LoadPdf(pdfDoc, 2);
                //StorageFile sf = await StorageFile.GetFileFromApplicationUriAsync(new Uri(bf.FileNameOnly));
                //var stream = await sf.OpenAsync(FileAccessMode.Read);

                //RichEditBoxBulletinContent.Document.LoadFromStream(TextSetOptions.FormatRtf, stream);
            }
        }