how to populate values in dropdownlist with a sharepoint custom list

SPWeb web = SPContext.Current.Web;
SPList list = web.GetListFromUrl("ListUrl");
SPQuery query = new SPQuery();

//I suppose field1 is the column which contains data in SPList
            //needs to be displayed in dropdownlist
            query.ViewFields = "<FieldRef Name='Field1' />"

;
SPListItemCollection spItemColl = list.GetItems(query);
foreach (SPListItem oItem in spItemColl)
{
ddlOutput.Items.Add(Convert.ToString(oItem["Field1"]));
}