//方法一

    DataSet dataSet = new DataSet();

    DataTable dt = dataSet.Tables[];

    for (int i = ; i < dt.Rows.Count; i++)

     {

      string strName = dt.Rows[i]["字段名"].ToString();

     }  

//方法二

DataSet myDataSet = new DataSet();

            foreach (DataRow myRow in myDataSet.Tables["temp"].Rows)

            {

                var str = myRow[].ToString();

            }

//方法三

  DataTable dt = new DataTable();

            foreach (DataRow dr in dt.Rows)

            {

                object value = dr["ColumnsName"];

            }

 //方法四 遍历datatable获取其中的值某一字段的值

            DataTable dt = new DataTable();

            string key = string.Empty;

            //DICNAME、CNNAME数据库表中字段，根据这2个字段值来筛选数据

            DataRow[] drs = dt.Select(string.Format("DICNAME='{0}' AND CNNAME='{1}'", ZiDuan, Zhi));

            if (drs.FirstOrDefault()  != null)

            {

                foreach (DataRow row in drs)

                {

                    //遍历筛选过的数据获取其中某个字段的值

                    key = ConvertObjectToString(row["SUBCODE"]);

                }

            }

       public string ConvertObjectToString(object obj)

        {

            if (obj != null)

            {

                return obj.ToString();

            }

            return string.Empty;

        }