如何在c#中计算两个日期之间的月差?
c#中是否有相当于VB的DateDiff()方法。我需要找出相隔数年的两个日期之间的月差。文档说我可以像这样使用TimeSpan:
TimeSpan ts = date1 - date2;
但这里的数据是以天为单位的。我不想把这个数字除以30,因为不是每个月都是30天,而且两个操作数的值相差很大,所以我担心除以30可能会得到错误的值。
有什么建议吗?
如何在c#中计算两个日期之间的月差?
c#中是否有相当于VB的DateDiff()方法。我需要找出相隔数年的两个日期之间的月差。文档说我可以像这样使用TimeSpan:
TimeSpan ts = date1 - date2;
但这里的数据是以天为单位的。我不想把这个数字除以30,因为不是每个月都是30天,而且两个操作数的值相差很大,所以我担心除以30可能会得到错误的值。
有什么建议吗?
当前回答
基于上面出色的DateTimeSpan工作,我将代码规范化了一些;这似乎很有效:
public class DateTimeSpan
{
private DateTimeSpan() { }
private DateTimeSpan(int years, int months, int days, int hours, int minutes, int seconds, int milliseconds)
{
Years = years;
Months = months;
Days = days;
Hours = hours;
Minutes = minutes;
Seconds = seconds;
Milliseconds = milliseconds;
}
public int Years { get; private set; } = 0;
public int Months { get; private set; } = 0;
public int Days { get; private set; } = 0;
public int Hours { get; private set; } = 0;
public int Minutes { get; private set; } = 0;
public int Seconds { get; private set; } = 0;
public int Milliseconds { get; private set; } = 0;
public static DateTimeSpan CompareDates(DateTime StartDate, DateTime EndDate)
{
if (StartDate.Equals(EndDate)) return new DateTimeSpan();
DateTimeSpan R = new DateTimeSpan();
bool Later;
if (Later = StartDate > EndDate)
{
DateTime D = StartDate;
StartDate = EndDate;
EndDate = D;
}
// Calculate Date Stuff
for (DateTime D = StartDate.AddYears(1); D < EndDate; D = D.AddYears(1), R.Years++) ;
if (R.Years > 0) StartDate = StartDate.AddYears(R.Years);
for (DateTime D = StartDate.AddMonths(1); D < EndDate; D = D.AddMonths(1), R.Months++) ;
if (R.Months > 0) StartDate = StartDate.AddMonths(R.Months);
for (DateTime D = StartDate.AddDays(1); D < EndDate; D = D.AddDays(1), R.Days++) ;
if (R.Days > 0) StartDate = StartDate.AddDays(R.Days);
// Calculate Time Stuff
TimeSpan T1 = EndDate - StartDate;
R.Hours = T1.Hours;
R.Minutes = T1.Minutes;
R.Seconds = T1.Seconds;
R.Milliseconds = T1.Milliseconds;
// Return answer. Negate values if the Start Date was later than the End Date
if (Later)
return new DateTimeSpan(-R.Years, -R.Months, -R.Days, -R.Hours, -R.Minutes, -R.Seconds, -R.Milliseconds);
return R;
}
}
其他回答
Public Class ClassDateOperation
Private prop_DifferenceInDay As Integer
Private prop_DifferenceInMonth As Integer
Private prop_DifferenceInYear As Integer
Public Function DayMonthYearFromTwoDate(ByVal DateStart As Date, ByVal DateEnd As Date) As ClassDateOperation
Dim differenceInDay As Integer
Dim differenceInMonth As Integer
Dim differenceInYear As Integer
Dim myDate As Date
DateEnd = DateEnd.AddDays(1)
differenceInYear = DateEnd.Year - DateStart.Year
If DateStart.Month <= DateEnd.Month Then
differenceInMonth = DateEnd.Month - DateStart.Month
Else
differenceInYear -= 1
differenceInMonth = (12 - DateStart.Month) + DateEnd.Month
End If
If DateStart.Day <= DateEnd.Day Then
differenceInDay = DateEnd.Day - DateStart.Day
Else
myDate = CDate("01/" & DateStart.AddMonths(1).Month & "/" & DateStart.Year).AddDays(-1)
If differenceInMonth <> 0 Then
differenceInMonth -= 1
Else
differenceInMonth = 11
differenceInYear -= 1
End If
differenceInDay = myDate.Day - DateStart.Day + DateEnd.Day
End If
prop_DifferenceInDay = differenceInDay
prop_DifferenceInMonth = differenceInMonth
prop_DifferenceInYear = differenceInYear
Return Me
End Function
Public ReadOnly Property DifferenceInDay() As Integer
Get
Return prop_DifferenceInDay
End Get
End Property
Public ReadOnly Property DifferenceInMonth As Integer
Get
Return prop_DifferenceInMonth
End Get
End Property
Public ReadOnly Property DifferenceInYear As Integer
Get
Return prop_DifferenceInYear
End Get
End Property
End Class
下面是一个使用VB的更简洁的解决方案。只适用于年、月、日的净日期。你也可以在c#中加载DateDiff库。
Date1必须<= date2
VB。网
Dim date1 = Now.AddDays(-2000)
Dim date2 = Now
Dim diffYears = DateDiff(DateInterval.Year, date1, date2) - If(date1.DayOfYear > date2.DayOfYear, 1, 0)
Dim diffMonths = DateDiff(DateInterval.Month, date1, date2) - diffYears * 12 - If(date1.Day > date2.Day, 1, 0)
Dim diffDays = If(date2.Day >= date1.Day, date2.Day - date1.Day, date2.Day + (Date.DaysInMonth(date1.Year, date1.Month) - date1.Day))
C#
DateTime date1 = Now.AddDays(-2000);
DateTime date2 = Now;
int diffYears = DateDiff(DateInterval.Year, date1, date2) - date1.DayOfYear > date2.DayOfYear ? 1 : 0;
int diffMonths = DateDiff(DateInterval.Month, date1, date2) - diffYears * 12 - date1.Day > date2.Day ? 1 : 0;
int diffDays = date2.Day >= date1.Day ? date2.Day - date1.Day : date2.Day + (System.DateTime.DaysInMonth(date1.Year, date1.Month) - date1.Day);
在我的情况下,需要计算从开始日期到下个月这一天的前一天或从月初到月底的完整月份。
例如:从1/1/2018到31/1/2018是一个完整的月 例2:从5/1/2018到4/2/2018是一个完整的月
基于此,我的解决方案如下:
public static DateTime GetMonthEnd(DateTime StartDate, int MonthsCount = 1)
{
return StartDate.AddMonths(MonthsCount).AddDays(-1);
}
public static Tuple<int, int> CalcPeriod(DateTime StartDate, DateTime EndDate)
{
int MonthsCount = 0;
Tuple<int, int> Period;
while (true)
{
if (GetMonthEnd(StartDate) > EndDate)
break;
else
{
MonthsCount += 1;
StartDate = StartDate.AddMonths(1);
}
}
int RemainingDays = (EndDate - StartDate).Days + 1;
Period = new Tuple<int, int>(MonthsCount, RemainingDays);
return Period;
}
用法:
Tuple<int, int> Period = CalcPeriod(FromDate, ToDate);
注意:在我的情况下,需要计算完整月份之后的剩余天数,所以如果不是你的情况,你可以忽略天数结果,甚至可以将方法返回值从元组更改为整数。
我在VB中检查了这个方法的用法。NET通过MSDN,它似乎有很多用途。c#中没有这样的内置方法。(即使这不是一个好主意)你可以在c#中调用VB。
将Microsoft.VisualBasic.dll添加到 你的项目作为参考 使用 Microsoft.VisualBasic.DateAndTime.DateDiff 在代码中
最精确的方法是以月为单位的分数返回差值:
private double ReturnDiffereceBetweenTwoDatesInMonths(DateTime startDateTime, DateTime endDateTime)
{
double result = 0;
double days = 0;
DateTime currentDateTime = startDateTime;
while (endDateTime > currentDateTime.AddMonths(1))
{
result ++;
currentDateTime = currentDateTime.AddMonths(1);
}
if (endDateTime > currentDateTime)
{
days = endDateTime.Subtract(currentDateTime).TotalDays;
}
return result + days/endDateTime.GetMonthDays;
}