create a list selectlist from DataSet. or convert a dataset into a selectlist item to populate a dropdownlist 

            List list = new List { };
            foreach(DataRow oDataRow in oCountry.DataSetCountry.Tables[0].Rows)
            {
                SelectListItem oSelectListItem = new SelectListItem { Value = (String)oDataRow["CountryCode"],Text = (String)oDataRow["CountryName"]};
                list.Add(oSelectListItem);  
            
            }
            ViewData["DDLCountry"] = list;