取dataset表中行的值

Question

 OracleConnection con_material = DB.CreateConnection();
                OracleDataAdapter sda_material = new OracleDataAdapter();
                sda_material.SelectCommand = new OracleCommand("select YP_BM from YYCGB_YPXX", con_material);
                DataSet ds_material = new DataSet();
                sda_material.Fill(ds_material, "material");
                int i=Count_material;//定义循环次数为油品的总数量
                string[] X = new string[i];//定义数组X，其长度为油品的总数量
                try
                {
                    for (i = 1; i < Count_material; i++) 
                    {
                        X[i] = ds_material.Tables["material"].Rows[i].ToString();//根据i的循环取出table中的第i行的值赋给数组X
                    }
                }
                catch
                {
                    Response.Write("油品描述读入有误！");
                }
问题是：X【i】不能取到表中的值，取到的是："System.Data.DataRow"

Answer 1

ds_material.Tables["material"].Rows[i]["YP_BM"].ToString();

Answer 2

 或者ds_material.Tables["material"].Rows[i][o].ToString();