从嵌套集合中获取值 (LINQ)

Question

我有Include 和几个ThenInclude 的LINQ 表达式

这里是代码

var test2 =  Loanapplications.Include(x=> x.LoanApplicationPositions)
.ThenInclude(x => x.PositionPlayterinvoices)
.ThenInclude(x=> x.PlayterInvoiceLoanpaymentagreements)
.Include(x => x.RecruitmentAgencyClient.Client)
.Select(x => new
{
    LoanId = x.LoanApplicationPositions.Select(x=> x.PositionPlayterinvoices),

我需要得到.ThenInclude(x=> x.PlayterInvoiceLoanpaymentagreements)下的LoanId

我怎样才能得到这个？

Answer 1

我会假设你的模型看起来像这样

class LoanApplication{
public List<LoanApplicationPosition> LoanApplicationPositions{get;set;}
}

class LoanApplicationPosition{
public List<PositionPlayterInvoce> PositionPlayterinvoices{get;set;}
}

class PositionPlayterInvoce{
public List<PlayterInvoiceLoanpaymentagreement> PlayterInvoiceLoanpaymentagreements{get;set;}
}

如果正确，那么您需要：

• 从该列表中选择一个 LoanApplicationPosition
• 从 PositionPlayterinvoices 列表中选择一个 PositionPlayterInvoce
• 从 PlayterInvoiceLoanpaymentagreements 列表中选择一个 PlayterInvoiceLoanpaymentagreements

类似的东西

var l = x.LoanApplicationPositions.FirstOrDefault();
var t = l.PositionPlayterinvoices.FirstOrDefault();
var LoanId = t.PlayterInvoiceLoanpaymentagreements.FirstOrDefault().LoanId

Answer 2

如果您有自定义投影，Select 在您的情况下，包含将被完全忽略。所以你必须自己写查询：

var query = 
    from la in Loanapplications
    from lap in la.LoanApplicationPositions
    from ppi in lap.PositionPlayterinvoices
    from pila in ppi.PlayterInvoiceLoanpaymentagreements
    select pila.LoadId;