private void EditBookButton_Click(object sender, RoutedEventArgs e)
 {
     if (BooksDataGrid.SelectedItems.Count > 0)
     {
         Book       book       = (Book)BooksDataGrid.SelectedItems[0];
         BookWindow bookWindow = new BookWindow();
         bookWindow.SetData(book);
         bookWindow.Show();
     }
 }
        private void AddBookButton_Click(object sender, RoutedEventArgs e)
        {
            BookWindow bookWindow = new BookWindow();

            bookWindow.Show();
        }