I know this is a pretty old topic, but I also had a same problem.
My solution:
how we fill the combobox:
foreach (KeyValuePair<int, string> item in listRegion)
{
combo.Items.Add(item.Value);
combo.ValueMember = item.Value.ToString();
combo.DisplayMember = item.Key.ToString();
combo.SelectedIndex = 0;
}
and that's how we get inside:
MessageBox.Show(combo_region.DisplayMember.ToString());
I hope it help someone