private void btnDel_Click(object sender, EventArgs e) { DialogResult question = MessageBox.Show("Are you sure?", "All books for this author will be deleted!", MessageBoxButtons.YesNo); if (question == DialogResult.Yes) { //========================= Author-un silinmesi ==================================== // downcast edirik ve comboBoxda secilmish author ID nomresini authorID-ye veririk string authorID = ((AuthorComboBox)cmbAuthorList.SelectedItem).Value; // AuthorList-den secilmish author ID-ye gore tapib veririk Author tipinde authorToDeleted-e // bir nov apcast olunur ki Author-un icinden lazim olana catsin Author authorToDeleted = AuthorList.GetAuthorByID(authorID); // AuthorList-den Author classina girib Authors siyahisindan // ID-ci uyqun geleni silirik AuthorList.Authors.Remove(authorToDeleted); //================================================================================== //=========== Silinen Author-un Book siyahisinin silinmesi =====================// // silinen group-un icindeki studentleri yeni List massivine yiqiriq List <Book> bookToBedeleted = BookList.GetBookByGroup(authorToDeleted); // ve hemin massiv siralanir ve siyahidaki bookName-ler silinir foreach (Book bookName in bookToBedeleted) { BookList.Books.Remove(bookName); } UpdateAuthorList(); } else { MessageBox.Show("You are cancelled deletion!"); } }