public AdminPanel() { InitializeComponent(); books_controller = new BooksController(); deposit_controller = new DepositController(); member_controller = new MemberController(); cbBookLang.Items.Add("Türkçe"); cbBookLang.Items.Add("İngilizce"); cbBookAuthor.DisplayMember = "name"; cbBookAuthor.ValueMember = "id"; cbBookAuthor.DataSource = books_controller.getAuthors(); cbBookPublisher.DisplayMember = "name"; cbBookPublisher.ValueMember = "id"; cbBookPublisher.DataSource = books_controller.getPubliser(); }