如何从另一个日期中减去一个日期？ [复制]

Question

假设我有两个日期：

现在日期：#8/10/2013 10:53:46 PM#

第二个日期是文件创建日期：

#7/10/2011 9:57:58 PM#

我想做类似的事情：Date.Now - FileDate。

这是我的代码：

Dim ddd As TimeSpan = Date.Now - SecondDate

时间跨度中没有“年份”属性。 （Year 属性应该是 2 2013 - 2011 = 2 ，但是有一个 days 属性 - 但我必须得到年/秒和月/秒）

更新：

谢谢大家，但我创建了一个函数：

Public Class Timee
        Private _Days As Integer
        Public Property Days() As Integer
            Get
                Return _Days
            End Get
            Set(ByVal value As Integer)
                _Days = value
            End Set
        End Property
        Private _Months As Integer
        Public Property Months() As Integer
            Get
                Return _Months
            End Get
            Set(ByVal value As Integer)
                _Months = value
            End Set
        End Property
        Private _Years As Integer
        Public Property Years() As Integer
            Get
                Return _Years
            End Get
            Set(ByVal value As Integer)
                _Years = value
            End Set
        End Property
    End Class
    Public Function GetTimeBetween(ByVal datee As Date, ByVal datee2 As Date) As Timee
        Dim tt As TimeSpan = datee - datee2
        Dim dd11 As Integer = tt.Days
        Dim bb1 As Integer
        Dim Month As Integer
        Dim Years1 As Integer
        Do Until dd11 <= 0
            bb1 = dd11
            dd11 = dd11 - 365
            Years1 = Years1 + 1
        Loop
        Years1 = Years1 - 1
        Dim Dayss As Integer
        Do Until bb1 <= 0
            Dayss = bb1
            bb1 = bb1 - 30
            Month = Month + 1
        Loop
        Dim tt1 As New Timee
        tt1.Days = Dayss
        tt1.Months = Month
        IF Years1 < 0 Then
           Years1 = 0
        End IF
        tt1.Years = Years1
        Return tt1
    End Function

希望它对某人有所帮助。

Answer 1

您可以使用 DateTime.Parse("date as a string") 将两者都转换为 DateTime 对象。 然后你会想要使用 DateTime.Subtract http://msdn.microsoft.com/en-us/library/8ysw4sby.aspx 然后你将拥有你想要的时间跨度，你可以在这里探索：http://msdn.microsoft.com/en-us/library/system.timespan_methods.aspx TotalDays 属性可以除以 365 以获得年份（请注意下面对此的公平挑战）。 几个月的计算会更复杂。

Answer 2

C#代码：

DateTime secondDate = ...;
var ddd = DateTime.Now - secondDate;
var days = ddd.TotalDays;

您无法获得“年”或“月”，因为并非所有年或月都具有相同的天数。

替代方案：

var now = DateTime.Now;
var totalYears = now.Year - secondDate.Year;

if (secondDate.Month > now.Month || (secondDate.Month == now.Month && secondDate.Day > now.Day))
{
    totalYears--;
}

var months = now.Month - secondDate.Mont;

if (secondDate.Day > now.Day)
{
    months--;
}

if (months < 0)
{
    months = 12 + months;
}

Answer 3

Dim ddd As New DateTime((Date.Now - SecondDate).Ticks)

另外，Jon Skeet 的 Noda Time 库中有一个函数。

Answer 4

问题是没有真正通用的一年定义。在日历中，一年是 365 或 366 天。在银行业，一年是 360 天，等等。

根据您的代码，我想说您想要日历年份的差异，因此您不能从时间跨度中做到这一点（因为时间跨度不知道一年是 365 天还是 366 天）。

所以你可以这样做：

var years = DateTime.Now.Year - fileDate.Year;

var dayInCurrentYear = fileDate.AddYears(years);

//if the day is later in the year than today's day go back one year
if(dayInCurrentYear > DateTime.Now)
{
   years--;
   dayInCurrentYear = dayInCurrentYear.AddYears(-1);
}

var span = DateTime.Now - dayInCurrentYear;

Console.WriteLine("File was created {0} years and {1} days ago", years, span.TotalDays);

Answer 5

TimeSpan 没有年份，因为TimeSpan 结构很简单，而且年份取决于文化以及起点和终点。这应该有效：

Dim zeroTime As New DateTime(1, 1, 1)
Dim a = #8/10/2013 10:53:46 PM#
Dim b = #7/10/2011 9:57:58 PM#

Dim span As TimeSpan = a - b
Dim years As Integer = (zeroTime + span).Year - 1  

您还可以查看支持该功能的 Jon Skeet 的 Noda-Time。