Question

这是我的问题：

DateTime previousDate = new DateTime();
DateTime currentDate = new DateTime();
foreach (ApproverVo approver in approvers)
{
    if (previousDate != null)
    {
        currentDate = (DateTime)approver.ApprovalDate;
        totalTimeSpan += (currentDate - previousDate).TotalDays;
        previousDate = currentDate;
    } else
        previousDate = (DateTime)approver.ApprovalDate;
}

当在开头声明上一个日期时，它包含默认值DateTime（）。我想要做的是找出是否已经为previousDate分配了正确的日期。

建议，谢谢

Answer 1

假设您的批准日期的值不等于DateTime.MinValue：

DateTime previousDate = DateTime.MinValue;
DateTime currentDate = new DateTime();
foreach (ApproverVo approver in approvers)
{
    if (previousDate != DateTime.MinValue)
    {
        currentDate = (DateTime)approver.ApprovalDate;
        totalTimeSpan += (currentDate - previousDate).TotalDays;
        previousDate = currentDate;
    } else
        previousDate = (DateTime)approver.ApprovalDate;
}

<强>更新

根据@mdmullinax的回答，上面的代码类似于：

DateTime previousDate = new DateTime();
DateTime currentDate = new DateTime();
foreach (ApproverVo approver in approvers)
{
    if (previousDate != new DateTime())
    {
        currentDate = (DateTime)approver.ApprovalDate;
        totalTimeSpan += (currentDate - previousDate).TotalDays;
        previousDate = currentDate;
    } else
        previousDate = (DateTime)approver.ApprovalDate;
}

Answer 2

检查{/ 1}}是否

previousDate == DateTime.MinValue

相当于

DateTime previousDate = new DateTime();

来自MSDN DateTime Structure文档：

DateTime previousDate = DateTime.MinValue;

确定新日期是否是默认的新DateTime（）

2 个答案: