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
这里有一个简单的解决方案，至少对我来说是有效的。它可能不是最快的，因为它在循环中使用了很酷的DateTime的AddMonth功能:
public static int GetMonthsDiff(DateTime start, DateTime end)
{
if (start > end)
return GetMonthsDiff(end, start);
int months = 0;
do
{
start = start.AddMonths(1);
if (start > end)
return months;
months++;
}
while (true);
}
其他回答
简单的修复。工作的100%
var exactmonth = (date1.Year - date2.Year) * 12 + date1.Month -
date2.Month + (date1.Day >= date2.Day ? 0 : -1);
Console.WriteLine(exactmonth);
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
label3.Text = new DateDifference(Convert.ToDateTime("2018-09-13"), Convert.ToDateTime("2018-11-15")).ToString();
label2.Text = new DateDifference(Convert.ToDateTime("2018-10-12"), Convert.ToDateTime("2018-11-15")).ToString();
DateDifference oDateDifference = new DateDifference(Convert.ToDateTime("2018-11-12"));
label1.Text = oDateDifference.ToString();
}
}
public class DateDifference
{
public DateTime start { get; set; }
public DateTime currentDAte { get; set; }
public DateTime origstart { get; set; }
public DateTime origCurrentDAte { get; set; }
int days { get; set; }
int months { get; set; }
int years { get; set; }
public DateDifference(DateTime postedDate, DateTime currentDAte)
{
this.start = this.removeTime(postedDate);
this.currentDAte = this.removeTime(currentDAte);
this.origstart = postedDate;
this.origCurrentDAte = currentDAte;
}
public DateDifference(DateTime postedDate)
{
DateTime currentDate_ = DateTime.Now;
this.start = this.removeTime(postedDate);
this.currentDAte = this.removeTime(currentDate_);
this.origstart = postedDate;
this.origCurrentDAte = currentDate_;
if (start > this.currentDAte)
{
throw new Exception("Current date is greater than date posted");
}
this.compute();
}
void compute()
{
while (this.start.Year <= this.currentDAte.Year)
{
if (this.start.Year <= this.currentDAte.Year && (this.start.AddMonths(1) <= this.currentDAte))
{
++this.months;
this.start = this.start.AddMonths(1);
}
if ((this.start.Year == this.currentDAte.Year) && (this.start >= this.currentDAte.AddMonths(-1) && this.start <= this.currentDAte))
{
break;
}
}
while (this.start.DayOfYear < this.currentDAte.DayOfYear)
{
++this.days;
this.start = start.AddDays(1);
}
if (this.months > 11)
{
while (this.months > 11)
{
++this.years;
this.months = months - 12;
}
}
}
public override string ToString()
{
if (this.start > this.currentDAte)
{
throw new Exception("Current date is greater than date posted");
}
String ret = this.ComposeTostring();
this.reset();
return ret;
}
private String ComposeTostring()
{
this.compute();
if (this.years > 0)
{
if (this.months > 0)
{
if (this.days > 0)
{
return String.Format("{0} year{1}, {2} month{3} && {4} Day{5} ago", this.years, plural(this.years), this.months, plural(this.months), this.days, plural(this.days));
}
return String.Format("{0} year{1}, {2} month{3} ago", this.years, plural(this.years), this.months, plural(this.months));
}
else
{
if (this.days > 0)
{
return String.Format("{0} year{1},{2} day{3} ago", this.years, plural(this.years), this.days, plural(this.days));
}
return String.Format("{0} year{1} ago", this.years, plural(this.years));
}
}
if (this.months > 0)
{
if (this.days > 0)
{
return String.Format("{0} month{1}, {2} day{3} ago", this.months, plural(this.months), this.days, plural(this.days));
}
else
{
return String.Format("{0} month{1} ago", this.months, plural(this.months));
}
}
if ((this.origCurrentDAte - this.origstart).Days > 0)
{
int daysDiff = (this.origCurrentDAte - this.origstart).Days;
this.origstart = this.origstart.AddDays(daysDiff);
int HoursDiff = (this.origCurrentDAte - this.origstart).Hours;
return String.Format("{0} day{1}, {2} hour{3} ago", daysDiff, plural(daysDiff), HoursDiff, plural(HoursDiff));
}
else if ((this.origCurrentDAte - this.origstart).Hours > 0)
{
int HoursDiff = (this.origCurrentDAte - this.origstart).Hours;
this.origstart = this.origstart.AddHours(HoursDiff);
int MinDiff = (this.origCurrentDAte - this.origstart).Minutes;
return String.Format("{0} hour{1}, {2} minute{3} ago", HoursDiff, plural(HoursDiff), MinDiff, plural(MinDiff));
}
else if ((this.origCurrentDAte - this.origstart).Minutes > 0)
{
int MinDiff = (this.origCurrentDAte - this.origstart).Minutes;
this.origstart = this.origstart.AddMinutes(MinDiff);
int SecDiff = (this.origCurrentDAte - this.origstart).Seconds;
return String.Format("{0} minute{1}, {2} second{3} ago", MinDiff, plural(MinDiff), SecDiff, plural(SecDiff));
}
else if ((this.origCurrentDAte - this.origstart).Seconds > 0)
{
int sec = (this.origCurrentDAte - this.origstart).Seconds;
return String.Format("{0} second{1}", sec, plural(sec));
}
return "";
}
String plural(int val)
{
return (val > 1 ? "s" : String.Empty);
}
DateTime removeTime(DateTime dtime)
{
dtime = dtime.AddHours(-dtime.Hour);
dtime = dtime.AddMinutes(-dtime.Minute);
dtime = dtime.AddSeconds(-dtime.Second);
return dtime;
}
public void reset()
{
this.days = 0;
this.months = 0;
this.years = 0;
this.start = DateTime.MinValue;
this.currentDAte = DateTime.MinValue;
this.origstart = DateTime.MinValue;
this.origCurrentDAte = DateTime.MinValue;
}
}
扩展的Kirks结构与ToString(格式)和持续时间(长ms)
public struct DateTimeSpan
{
private readonly int years;
private readonly int months;
private readonly int days;
private readonly int hours;
private readonly int minutes;
private readonly int seconds;
private readonly int milliseconds;
public DateTimeSpan(int years, int months, int days, int hours, int minutes, int seconds, int milliseconds)
{
this.years = years;
this.months = months;
this.days = days;
this.hours = hours;
this.minutes = minutes;
this.seconds = seconds;
this.milliseconds = milliseconds;
}
public int Years { get { return years; } }
public int Months { get { return months; } }
public int Days { get { return days; } }
public int Hours { get { return hours; } }
public int Minutes { get { return minutes; } }
public int Seconds { get { return seconds; } }
public int Milliseconds { get { return milliseconds; } }
enum Phase { Years, Months, Days, Done }
public string ToString(string format)
{
format = format.Replace("YYYY", Years.ToString());
format = format.Replace("MM", Months.ToString());
format = format.Replace("DD", Days.ToString());
format = format.Replace("hh", Hours.ToString());
format = format.Replace("mm", Minutes.ToString());
format = format.Replace("ss", Seconds.ToString());
format = format.Replace("ms", Milliseconds.ToString());
return format;
}
public static DateTimeSpan Duration(long ms)
{
DateTime dt = new DateTime();
return CompareDates(dt, dt.AddMilliseconds(ms));
}
public static DateTimeSpan CompareDates(DateTime date1, DateTime date2)
{
if (date2 < date1)
{
var sub = date1;
date1 = date2;
date2 = sub;
}
DateTime current = date1;
int years = 0;
int months = 0;
int days = 0;
Phase phase = Phase.Years;
DateTimeSpan span = new DateTimeSpan();
while (phase != Phase.Done)
{
switch (phase)
{
case Phase.Years:
if (current.AddYears(years + 1) > date2)
{
phase = Phase.Months;
current = current.AddYears(years);
}
else
{
years++;
}
break;
case Phase.Months:
if (current.AddMonths(months + 1) > date2)
{
phase = Phase.Days;
current = current.AddMonths(months);
}
else
{
months++;
}
break;
case Phase.Days:
if (current.AddDays(days + 1) > date2)
{
current = current.AddDays(days);
var timespan = date2 - current;
span = new DateTimeSpan(years, months, days, timespan.Hours, timespan.Minutes, timespan.Seconds, timespan.Milliseconds);
phase = Phase.Done;
}
else
{
days++;
}
break;
}
}
return span;
}
}
这里有一个简单的解决方案，至少对我来说是有效的。它可能不是最快的，因为它在循环中使用了很酷的DateTime的AddMonth功能:
public static int GetMonthsDiff(DateTime start, DateTime end)
{
if (start > end)
return GetMonthsDiff(end, start);
int months = 0;
do
{
start = start.AddMonths(1);
if (start > end)
return months;
months++;
}
while (true);
}
您可以使用以下扩展: 代码
public static class Ext
{
#region Public Methods
public static int GetAge(this DateTime @this)
{
var today = DateTime.Today;
return ((((today.Year - @this.Year) * 100) + (today.Month - @this.Month)) * 100 + today.Day - @this.Day) / 10000;
}
public static int DiffMonths(this DateTime @from, DateTime @to)
{
return (((((@to.Year - @from.Year) * 12) + (@to.Month - @from.Month)) * 100 + @to.Day - @from.Day) / 100);
}
public static int DiffYears(this DateTime @from, DateTime @to)
{
return ((((@to.Year - @from.Year) * 100) + (@to.Month - @from.Month)) * 100 + @to.Day - @from.Day) / 10000;
}
#endregion Public Methods
}
实现!
int Age;
int years;
int Months;
//Replace your own date
var d1 = new DateTime(2000, 10, 22);
var d2 = new DateTime(2003, 10, 20);
//Age
Age = d1.GetAge();
Age = d2.GetAge();
//positive
years = d1.DiffYears(d2);
Months = d1.DiffMonths(d2);
//negative
years = d2.DiffYears(d1);
Months = d2.DiffMonths(d1);
//Or
Months = Ext.DiffMonths(d1, d2);
years = Ext.DiffYears(d1, d2);
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