交叉表查询 (LINQ to DataSet)

// Fill the DataSet.DataSet ds = new DataSet();ds.Locale = CultureInfo.InvariantCulture;FillDataSet(ds);DataTable orders = ds.Tables["SalesOrderHeader"];DataTable details = ds.Tables["SalesOrderDetail"];var query =    from order in orders.AsEnumerable()    join detail in details.AsEnumerable()    on order.Field<int>("SalesOrderID") equals        detail.Field<int>("SalesOrderID")    where order.Field<bool>("OnlineOrderFlag") == true    && order.Field<DateTime>("OrderDate").Month == 8    select new    {        SalesOrderID =            order.Field<int>("SalesOrderID"),        SalesOrderDetailID =            detail.Field<int>("SalesOrderDetailID"),        OrderDate =            order.Field<DateTime>("OrderDate"),        ProductID =            detail.Field<int>("ProductID")    };foreach (var order in query){    Console.WriteLine("{0}/t{1}/t{2:d}/t{3}",        order.SalesOrderID,        order.SalesOrderDetailID,        order.OrderDate,        order.ProductID);}