private void DeleteBook()
 {
     AuthorBookList.Remove(SelectedBook);
     AllBookList.Remove(SelectedBook);
     CurrentBook  = null;
     SelectedBook = null;
     MessageBox.Show("Book Deleted");
 }
        private void SaveBook()
        {
            if (SelectedAuthor != null)
            {
                BookModel bk = new BookModel();
                bk.Title      = CurrentBook.Title;
                bk.Publisher  = CurrentBook.Publisher;
                bk.BookType   = CurrentBook.BookType;
                bk.Price      = CurrentBook.Price;
                bk.BookNumber = initialbook += 1;
                AuthorBookList.Add(bk);
                AllBookList.Add(bk);
            }
            else
            {
                MessageBox.Show("Must create author first!");
            }

            SelectedBook = null;
            BV.Close();
        }