Problem sa djelom koda u C#

Code:
string izmjeni_stavka;
        
        public string primi_stavku()
        {
            if (stavka.SelectedIndex < -1)
                return "Nista nije odabrano";
            return stavka.SelectedItem.ToString();
        }

Code:
for (int x = 0; x < redniBroj-1; x++)
                {
                    redni_br.Items.RemoveAt(x);
                    stavka.Items.RemoveAt(x);
                    kolicina.Items.RemoveAt(x);
                    cijena.Items.RemoveAt(x);
                    mjerna_jed.Items.RemoveAt(x);
                }