不使用组获取组总和.第行中的Sum()

Question

以下查询有效，但我希望在不使用grp的情况下获得相同的结果。Sum((。我们能做到吗？

from item in (await VehicleReplaceCostDataAsync())
group item by (item.type, item.size, item.ADA, item.eseq) into grp
orderby (grp.Key.eseq, grp.Key.size, grp.Key.ADA)
select new VehicleReplacementCost
{
type = grp.Key.type,
size = grp.Key.size,
ADA = grp.Key.ADA,
count = grp.Sum(x => x.count),
cost = grp.Sum(x => x.cost),
Fcount = grp.Sum(x => x.Fcount),
Fcost = grp.Sum(x => x.Fcost),
eseq = grp.Key.eseq,
}).ToList();

Answer 1

也许使用.Aggregate()？[docs]

count = grp.Aggregate(0, (a, b) => a + b.count)

Answer 2

感谢Astrid的回答。它看起来很好，但我没有测试它。我的同事通过使用收益率给出了这个解决方案：

var groups = costs
.GroupBy(type => (type.SystemId, type.Type, type.Size, type.ADA, type.Eseq))
.OrderBy(group => (group.Key.SystemId, group.Key.Eseq, group.Key.Size, group.Key.ADA));

foreach (var group in groups)
{
var result = new ProgramGuideVehicleCostRow
{
SystemId = group.Key.SystemId,
Type = group.Key.Type,
Size = group.Key.Size,
ADA = group.Key.ADA,
};
foreach (var row in group)
{
result.Cost += row.Cost;
result.Fcost += row.Fcost;
result.Count += row.Count;
result.Fcount += row.Fcount;
}
yield return result;
}