DataSet 中可以有多個 DataTable；DataTable 中有多個DataColumn (列名)，多個Rows (資料行)。

DataSet data = new DataSet("資料集");
            DataTable dataTable1 = new DataTable("資料表1");
            //DataTable dataTable2 = new DataTable("資料表2");
            data.Tables.AddRange(new DataTable[] { dataTable1 });
            //data.Tables.Add(dataTable2);
            DataColumn age = new DataColumn("年齡",typeof(int));
            DataColumn name = new DataColumn("姓名",typeof(String));
            DataColumn hobby = new DataColumn("愛好",typeof(String));
            dataTable1.Columns.AddRange(new DataColumn[] { age, name, hobby });
            dataTable1.Rows.Add(18,"liuyan樣","運動");
            dataTable1.Rows.Add(13, "sdg樣", "健身");
            dataTable1.Rows.Add(17, "asfagsw樣", "跑步");

            //遍歷DataSet中的資料
            foreach (DataTable dt in data.Tables) {
                foreach(DataRow row in dt.Rows) {
                    String myage = row[0].ToString();
                    String myname = row[1].ToString();
                    String myhobby = row[2].ToString();

                }
            }