//多表多行多列的情况

foreach (DataTable dt in YourDataset.Tables) //遍历所有的datatable
{ 
foreach (DataRow dr in dt.Rows) ///遍历所有的行
foreach (DataColumn dc in dt.Columns) //遍历所有的列
Console.WriteLine(“{0}, {1}, {2}”, dt.TableName,

dc.ColumnName, dr[dc]); //表名,列名,单元格数据
}

//遍历一个表多行多列

foreach(DataRow mDr in dataSet.Tables[0].Rows ) 
{ 
foreach(DataColumn mDc in dataSet.Tables[0].Columns) 
{ 
Console.WriteLine(mDr[mDc].ToString()); 
} 
}

DataSet2 ds = new DataSet2();
SqlDataAdapter da1 = new SqlDataAdapter(str, conn);
da1.Fill(ds, "table");

//已经装载到DataSet数据集中了

for (int k = 0; k < ds.Tables["table"].Rows.Count; k++)
                {
                    for (int j = 0; j < ds.Tables["table"].Columns.Count; j++)
                    {

if (ds.Tables["table"].Rows[k]["emergency"].ToString().Trim() == "1")
                        {

ds.Tables["table"].Rows[k]["emergency"] = "合格";
                        }
                        else if (ds.Tables["table"].Rows[k]["emergency"].ToString().Trim() == "0")
                        {
                            //emergency = "处置";
                            ds.Tables["table"].Rows[k]["emergency"] = "处置";

}
                    }
                } 
   ds.AcceptChanges();