private void CreateButton_Click(object sender, EventArgs e) { if (CheckingFields()) { var books = (BookLibrary)BookComboBox.SelectedItem; int year; int.TryParse(YeartextBox.Text, out year); var author = new AuthorLibrary { Name = AuthortextBox.Text, Gender = GendertextBox.Text, YearOfBirth = year, BookLibrary = books }; dataAccess.CreateAuthor(author); Close(); } }