private void buttonOK_Click(object sender, EventArgs e) { switch (ComboBoxSelected.SelectedIndex) { case 0: { Book book = new Book(this); book.Show(); Hide(); break; } case 1: { MagazineArticle article = new MagazineArticle(this); article.Show(); Hide(); break; } case 2: { DigestArticle article = new DigestArticle(this); article.Show(); Hide(); break; } case 3: { NewspaperArticle article = new NewspaperArticle(this); article.Show(); Hide(); break; } case 4: { Dissertation dis = new Dissertation(this); dis.Show(); Hide(); break; } case 5: { Abstract abs = new Abstract(this); abs.Show(); Hide(); break; } case 6: { InternetResource res = new InternetResource(this); res.Show(); Hide(); break; } default: break; } }