交叉表查询 (LINQ to DataSet)_c# 交叉表-优快云博客

本文通过使用LINQ查询从两个数据表中筛选出所有在线订单及其详细信息，并展示了如何将这些信息打印到控制台。示例代码利用了C#的类型安全特性，确保了查询结果的准确性。

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// 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);
}