如何在lambda表达式中使用运算符（if else） [英] How to use operators(if else) in lambda expression

问题描述

 CurrentFinancialMovementData movementData = keys.OrderByDescending（s => s.LatestReserveDate ?? s.LatestRecoveryReserveDate）.ThenByDescending（x => x.ReserveDaySequence）.First（）; 
 
 CurrentFinancialMovementData movementDataReserve = keys.Where（s => s.AmountType ==（short）StaticValues.AmountType.Reserve）.OrderByDescending（a => a.LatestReserveDate）.ThenByDescending（x => ; x.ReserveDaySequence）.FirstOrDefault（）; 
 
 CurrentFinancialMovementData movementDataRecoveryReserve = keys.Where（s => s.AmountType ==（short）StaticValues.AmountType.RecoveryReserve）.OrderByDescending（a => a.LatestRecoveryReserveDate）.ThenByDescending（x => ; x.ReserveDaySequence）.FirstOrDefault（）; 

我想检查我的movingData AmountType.Reserve然后它必须采用LatestReserveDate并且如果我的movementData是AmountType.RecoveryReserve，它应该采用LatestRecoveryReserveDate。我想在movingData中处理这种情况。任何人都可以帮助我吗？



我尝试过：



我试过：

if（keys.Any（s => s.AmountType ==（short）StaticValues.AmountType.Reserve））

{CurrentFinancialMovementData movementData = keys .OrderByDescending（s => s.LatestReserveDate）.ThenByDescending（x => x.ReserveDaySequence）.First（）;

}

else if（keys.Any（s => s.AmountType ==（short）StaticValues.AmountType.RecoveryReserve））

{CurrentFinancialMovementData movementData = keys.OrderByDescending（s => s.LatestRecoveryReserveDate）.ThenByDescending（x => x.ReserveDaySequence）.First（）;

}

解决方案

我会这样做：

 CurrentFinancialMovementData movementData =  null ; 
 {
 CurrentFinancialMovementData movement1 = keys.OrderByDescending（s = >  s.LatestReserveDate）
 .ThenByDescending（x = >  x.ReserveDaySequence）
 .FirstOrDefault（x => x.AmountType == StaticValues.AmountType.Reserve）; 
 CurrentFinancialMovementData movement2 = keys.OrderByDescending（s = >  s.LatestRecoveryReserveDate）
 .ThenByDescending（x = >  x.ReserveDaySequence）
 .FirstOrDefault（x => x.AmountType == StaticValues.AmountType.RecoveryReserve）; 
 movementData =（移动==  null ）？运动2：运动; 
} 
 
  //  警告 - 仍然有可能moveData可能为null ，但 
  //  在确定这一事实的过程中优雅地处理，以及你是什么 
  //  这些信息取决于你。 

CurrentFinancialMovementData movementData = keys.OrderByDescending(s => s.LatestReserveDate ?? s.LatestRecoveryReserveDate).ThenByDescending(x => x.ReserveDaySequence).First();

CurrentFinancialMovementData movementDataReserve = keys.Where(s => s.AmountType == (short)StaticValues.AmountType.Reserve).OrderByDescending(a => a.LatestReserveDate).ThenByDescending(x => x.ReserveDaySequence).FirstOrDefault();

CurrentFinancialMovementData movementDataRecoveryReserve = keys.Where(s => s.AmountType == (short)StaticValues.AmountType.RecoveryReserve).OrderByDescending(a => a.LatestRecoveryReserveDate).ThenByDescending(x => x.ReserveDaySequence).FirstOrDefault();

I want to check if my movementData AmountType.Reserve then it must take LatestReserveDate and if my movementData is AmountType.RecoveryReserve than it should take LatestRecoveryReserveDate. I want to handle this situation in movementData. Can anyone help me in this ?

What I have tried:

I tried:
if (keys.Any(s => s.AmountType == (short)StaticValues.AmountType.Reserve))
{ CurrentFinancialMovementData movementData = keys.OrderByDescending(s => s.LatestReserveDate).ThenByDescending(x => x.ReserveDaySequence).First();
}
else if (keys.Any(s => s.AmountType == (short)StaticValues.AmountType.RecoveryReserve))
{ CurrentFinancialMovementData movementData = keys.OrderByDescending(s => s.LatestRecoveryReserveDate).ThenByDescending(x => x.ReserveDaySequence).First();
}

解决方案

I would do it this way:

CurrentFinancialMovementData movementData = null;
{
    CurrentFinancialMovementData movement1 = keys.OrderByDescending(s => s.LatestReserveDate)
                                                 .ThenByDescending(x => x.ReserveDaySequence)
                                                 .FirstOrDefault(x=>x.AmountType == StaticValues.AmountType.Reserve);
    CurrentFinancialMovementData movement2 = keys.OrderByDescending(s => s.LatestRecoveryReserveDate)
                                                 .ThenByDescending(x => x.ReserveDaySequence)
                                                 .FirstOrDefault(x=>x.AmountType == StaticValues.AmountType.RecoveryReserve);
    movementData = (movement == null) ? movement2 : movement;
}

// caveat - there's still a chance that movementData could be null, but it's 
// handled gracefully in the process of determining that fact, and what you 
// do with that info is up to you.

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