Combobox update problem

Question

hey guys...i am loading my combobox from my Hosting table and there i save ipAdresses with ","(if it is more than one)..and i load them combobox by splitting...but the thing is when i want to update the record i cant save them back as i loaded at the beginning..i use that codes to update 

string NsDizi = hostForm.cmbNs.Text;
for (int i = 0; i < hostForm.cmbNs.Items.Count-1; i++)
{
   NsDizi += hostForm.cmbNs.Items[i].ToString() + ",";
}
hostForm.textBox1.Text = NsDizi;
cmmd.Parameters["@_ns"].Value = hostForm.textBox1.Text;

  so how i can update my datas in combobox