使用sum进行LINQ到XML分组

我目前正在使用此xml（这是一个很小的子集）：

---

我会先变换，然后分组/求和：

var query = from element in doc.Descendants("order")
            select new { Customer = (int) element.Element("customer"),
                         Total = (decimal) element.Element("total") }
            into order
            group order.Total by order.Customer into g
            select new { Customer = g.Key, Total = g.Sum() };

foreach (var result in query)
{
    Console.WriteLine("customer {0} with a total of {1}",
                      result.Customer, result.Total);
}

（当然，您也可以用点表示法来完成这一切。）

customer 1035 with a total of 15.6
customer 1036 with a total of 5.6

var query = from element in doc.Descendants("order")
            select new { Customer = (int) element.Element("customer"),
                         Total = (decimal) element.Element("total") }
            into order
            group order.Total by order.Customer into g
            select new { Customer = g.Key, Total = g.Sum() };

foreach (var result in query)
{
    Console.WriteLine("customer {0} with a total of {1}",
                      result.Customer, result.Total);
}