private void addCopiesBtn_Click(object sender, EventArgs e)
        {
            int copies = Int32.Parse(bookCopyTextbox.Text);
            Book motherBook = booksComboBox.SelectedItem as Book;
            {

                while (copies>0)
                {
                    BookCopy newCopy = new BookCopy()
                    {
                        _book = motherBook //bokkopians Book-parameter får samma värde som motherBook, dvs den valda boken från
                                                                                                                              combobox.
                    };


                    _bookCopyService.Create(newCopy);     //Sparar kopian av motherBook till databasen.
                    copies--;
                }


                clearAll();
            }
        }