向不在 While 循环中执行的 C# 可空 DateTime 对象添加天数

Question

我正在这里编写一些生产代码，并且不得不在已经有点问题的代码之上添加一些我自己设计的代码。我有一个循环可以帮助根据特定的支付期计算日期。

我遇到的问题是，当使用 DateTime?.Value.AddDays() 函数调用向它们添加值时，我的 Nullable DateTime 对象根本没有改变。当我运行通过此代码时， nextPayDate 对象及其值保持不变，即使我在循环期间添加到它也是如此。上述行为没有用，而且会造成无限循环。想法？

public static List<DateTime?> GetLPSPaymentDates(Applicant applicant, int loanTermType, DateTime deliveryConfirmationDate)
{

    if (applicant == null)
    {
        throw new Exception("The applicant you are wanting to set an LPS for is null");
    }

    DateTime? firstPaymentDate = DateTime.Today;
    DateTime? secondPaymentDate = DateTime.Today;
    DateTime? lastPayDate = applicant.MainEmployer.LastPayDate;
    DateTime? nextPayDate = applicant.MainEmployer.NextPayDate;

    DateTime? earliestPossiblePaymentDate =   deliveryConfirmationDate.AddDays(10);

    int daysToAdd = 0;
    if (lastPayDate != null && nextPayDate != null)
    {
        var tempDate = nextPayDate;
        while (tempDate.Value <= earliestPossiblePaymentDate.Value)
        {
            daysToAdd =     IncrementPaymentDateByTermType((TermTypes)loanTermType);
            nextPayDate.Value.AddDays(daysToAdd);
            firstPaymentDate.Value.AddDays(daysToAdd);
        }
        if (firstPaymentDate == DateTime.Today)
        {
            firstPaymentDate = nextPayDate;
        }
        secondPaymentDate = firstPaymentDate.Value.AddDays(daysToAdd); 
    }
    else
    {
        throw new Exception("Could not find applicant's last or next pay date.");
    }

    List<DateTime?> firstAndSecondDates = new List<DateTime?>()
    {
        firstPaymentDate,
        secondPaymentDate
    };

    return firstAndSecondDates;

}

public static int IncrementPaymentDateByTermType(TermTypes termType)
{
    int numberOfDaysToAdd;

    switch (termType)
    {
        case TermTypes.BiWeekly:
            numberOfDaysToAdd = 14; 
            break;
        case TermTypes.Weekly:
            numberOfDaysToAdd = 7;
            break;
        default:
            numberOfDaysToAdd = 1;
            break;
    }
    return numberOfDaysToAdd;
}

Answer 1

没有测试，但这应该会有所帮助（假设你的 while 循环逻辑是正确的）

while (tempDate.Value <= earliestPossiblePaymentDate.Value)
{
    daysToAdd = IncrementPaymentDateByTermType((TermTypes)loanTermType);
    tempDate = nextPayDate.Value.AddDays(daysToAdd); // <<= updating tempDate
    firstPaymentDate.Value.AddDays(daysToAdd);
}

Answer 2

AddDays returns 一个新对象作为结果，而不是更新现有对象。尝试：

daysToAdd = IncrementPaymentDateByTermType((TermTypes)loanTermType);
nextPayDate = nextPayDate.Value.AddDays(daysToAdd);
firstPaymentDate = firstPaymentDate.Value.AddDays(daysToAdd);

向不在 While 循环中执行的 C# 可空 DateTime 对象添加天数

Adding Days To C# Nullable DateTime Object Not Performing In While Loop

c#

datetime

loops

for-loop

nullable