vb.net 总和和组 linq
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Sum and group linq
提问by nat
I have tried to sort this out myself but I am having to do it in VB which confuddles me even more. basically I have a lit of objects
我试图自己解决这个问题，但我不得不在 VB 中进行，这让我更加困惑。基本上我有一盏灯
List<Pax> paxes;
one of the Pax properties is Voucher, which in turn has some properties such as ID, and Price
Pax 属性之一是 Voucher，它又具有一些属性，例如 ID 和 Price
what I want to do is select out of a list of Pax, a list of Vouchers and their cumulative prices
我想要做的是从 Pax 列表、Vouchers 列表及其累计价格中选择
so from
Pax1 - Voucher{ VoucherDesc = 10 percent off, VoucherCode = 10-OFF, Price = ￡150}
Pax2 - Voucher{ VoucherDesc = 10 percent off, VoucherCode = 10-OFF, Price = ￡120}
Pax3 - Voucher{ VoucherDesc = Buy one get one free, VoucherCode = BOGOF, Price = ￡300}
to
{10 percent off, 10-OFF, ￡270 }
{Buy one get one free, BOGO, ￡300 }
I am sure this is possible with a bit of linq and grouping, but I am completely stumped
我确信这可以通过一些 linq 和分组来实现，但我完全被难住了
presume it is along the lines of
假设它是沿着
dim newlist = from p in paxes group p by p.VoucherCode into g _
select new With {g. ..}
yes this has to end up in VB but as I find that rather painful, figured I would make more sense of it in C# however, as the VB syntax is pure evil, if someone could post both, I might finally be able to make sense of what its doing. as the code converter doesn't seem to play nicely with extended linq queries.
是的，这必须在 VB 中结束，但因为我发现这相当痛苦，我想我会在 C# 中更有意义，但是，因为 VB 语法是纯粹的邪恶，如果有人可以同时发布两者，我可能最终能够理解它在做什么。因为代码转换器似乎不能很好地处理扩展的 linq 查询。
any help much appreciated
非常感谢任何帮助
采纳答案by Sergey Berezovskiy
Assume price is a decimal or double (not string):
假设价格是十进制或双精度（不是字符串）：
var query = from v in paxes.Select(p => p.Voucher)
group v by new {v.VoucherDesc, v.VoucherCode } into g
select new {
Desc = g.Key.VoucherDesc,
Code = g.Key.VoucherCode,
Total = g.Sum(x => x.Price)
};
Update: you question was initially tagged with C#, thus this is a C# solution. Hope you can translate it to VB. If price is string, then just add parsing of value. E.g.
更新：您的问题最初是用 C# 标记的，因此这是一个 C# 解决方案。希望你能把它翻译成VB。如果价格是字符串，那么只需添加值的解析。例如
Total = g.Sum(x => Double.Parse(x.Price.Replace("￡", ""))
回答by nat
thanks for the replies
感谢您的回复
managed to convert that to vb thus
设法将其转换为 vb 因此
Dim q = From v In paxes.Select(Function(p) p.Voucher).Where(Function(v) v IsNot Nothing) _
Group v By v.OptionID, v.VoucherCode, v.Description Into Group _
Select OptionID, VoucherCode, Description, TotalDiscount = Group.Sum(Function(v) v.Price)
fields are named a little different but it works fine helped by lazyb's post and this link: http://msdn.microsoft.com/en-us/vstudio/bb688088.aspx
字段的名称略有不同，但在lazyb 的帖子和此链接的帮助下它可以正常工作：http: //msdn.microsoft.com/en-us/vstudio/bb688088.aspx
