sql查询结果存入DataTable，然后从DataTable取数据

public static DataTable SqlConnectionInformation()
{
string connstr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString; 
DataTable dt = new DataTable();
using (SqlConnection conn = new SqlConnection(connstr))
{
if (conn.State == ConnectionState.Closed)
{
conn.Open(); 
} 
string sql = "select * from table";
SqlCommand com = new SqlCommand(sql, conn);
SqlDataAdapter adapter = new SqlDataAdapter(com);
adapter.Fill(dt); 
}

return dt; 

}

 for (int i = 0; i < dt.Rows.Count; i++)
            {
                string s = "select count(*) from " + dt.Rows[i]["AliasName"] + ".dbo.web_historydata where factoryid=" + dt.Rows[i]["FactoryID"] + " and  datetime >dateadd(HOUR,-1,GetDate())";
                int count = my_SqlHelper.SelectCounts(s);
                if (count<=0)
                {
                    Log.Save("蜀云泉真帅啊");
                }
            }

　　如果不知道列名是啥子的话，也可以这样遍历

   for (int i = 0; i < dataTable.Rows.Count; i++)
            {
                for (int j = 0; j < dataTable.Columns.Count; j++)
                {
                    Console.WriteLine(dataTable.Rows[i][j].ToString()); 
                } 
            }