c# - 在 LINQ 中加入 + 组 + 聚合

Question

我有以下查询，我将其放入DataGrid：

var balancePerAccount = from bal in data.balanceDetails
                        join acc in data.userPaymentDetails on bal.userName equals acc.userName
                        where bal.paymentID == 0
                        group bal by bal.userName into g
                        where g.Sum(p => p.rebateBeforeService) >= 20
                        select new
                        {
                            Username = g.Key,
                            Amount = g.Sum(p => p.rebateBeforeService),
                        };
dgPaymentsPending.DataSource = balancePerAccount;
dgPaymentsPending.DataBind();

我想做的是acc在select. 例如我想添加PaymentProvider = acc.PaymentProvider. 我尝试了所有我能想到的方法，包括First()从组中获取并尝试从那里访问它，但我似乎找不到访问它的方法。我可能只是遗漏了一些非常简单的东西，但我已经在 Google 上搜索了一段时间，但似乎找不到可比较的示例。有人有想法吗？

Answer 1

使用匿名类型扩展分组源：new { bal, acc }然后使用First

var balancePerAccount = from bal in data.balanceDetails
                        join acc in data.userPaymentDetails on bal.userName equals acc.userName
                        where bal.paymentID == 0
                        group new { bal, acc } by bal.userName into g
                        where g.Sum(p => p.bal.rebateBeforeService) >= 20
                        select new
                        {
                            Username = g.Key,
                            PaymentProvider = g.FirstOrDefault().acc.PaymentProvider,
                            Amount = g.Sum(p => p.bal.rebateBeforeService),
                        };