public static void BoundComboBox(ComboBoxEdit editor, DataTable dt, string fieldName)
{
    editor.Properties.Items.Clear();
    editor.Properties.DropDownItemHeight = 25;

    foreach (DataRow R in dt.Rows)
    {
        editor.Properties.Items.Add(R[fieldName]);
    }

    if (dt.Rows.Count > 0)
        editor.Properties.DropDownRows = 10;
    else
        editor.Properties.DropDownRows = dt.Rows.Count;
}