private void addButton_Click(object sender, RoutedEventArgs e)
{
NewPhoto = new Photograph(
titleTextBox.Text,
artistTextBox.Text,
takenDatePicker.SelectedDate.Value,
descriptionTextBox.Text,
imagePathTextBox.Text,
keywordsTextBox.Text.Split(',').Select(keyword => keyword.Trim()).ToArray()
);
this.DialogResult = true;
}