private void fileChooseButton_Click(object sender, EventArgs e)
        {
            // 画像を選ぶ
            var task = new PhotoChooserTask
            {
                PixelHeight = 800,
                PixelWidth = 600,
                ShowCamera = true
            };

            task.Completed += (ps, pe) =>
                {
                    if (pe.TaskResult == TaskResult.OK && pe.Error == null)
                    {
                        this.originBitmap = ConvertToWriteableBitmap(pe.ChosenPhoto);

                        this.editedBitmap = ApplyYey(Grayscare(this.originBitmap));
                        this.pictureImage.Source = editedBitmap.ToBitmapImage();

                        this.fileSaveButton.IsEnabled = true;
                        this.startMessageGrid.Visibility = System.Windows.Visibility.Collapsed;
                    }
                    else if (pe.TaskResult == TaskResult.Cancel && pe.Error != null)
                    {
                        MessageBox.Show(
                            "PCでZune Softwareと同期中の可能性があります。\n" +
                            "Zune Softwareを終了するか、端末をPCから切断してもう一度実行して下さい。",
                            "エラー",
                            MessageBoxButton.OK);
                    }
                };

            task.Show();
        }