使用LINQ列表中的Groupby列表

Question

我有两节课:

class Customer
{
    public string Name { get; set; }
    public string ZipCode { get; set; }
    public List<Order> OrderList { get; set; }
}

class Order
{
    public string OrderNumber { get; set; }
}

使用LINQ,我想通过ZipCode获取Orders组列表.如果Zipcode"12121"有10个客户,每个有2个订单,那么它应该只返回一个包含20个订单列表的Zipcode.

我试图这样做,但不能弄清楚什么是错的

var orders = br.CustOrderList
.Select(r => new
{
    r.ZipCode,
    r.Name,
    r.OrderList
})
.GroupBy(x => new { x.ZipCode, x.OrderList}); 

有什么帮助吗？

Answer 1

这应该做你想要的:

var orders = br.CustOrderList
    .GroupBy(x => x.ZipCode)
    .Select(g => new
    {
        ZipCode = g.Key,
        Orders = g.SelectMany(x => x.OrderList)
    });