我有一个包含2个日期属性的类：FirstDay和LastDay。 LastDay可以为空。我想以"x year(s) y day(s)"的格式生成一个字符串。如果总年数小于1，我想省略年份部分。如果总天数小于1，我想省略日期部分。如果年份或天数为0，则应分别说“日/年”，而不是“天/年”。
示例：
2。2年：“2年73天”
1.002738年：“1年1天”
0。2年：“73天”
2年：“2年”
我的工作有多长，但很长：
private const decimal DaysInAYear = 365.242M;
public string LengthInYearsAndDays
{
get
{
var lastDay = this.LastDay ?? DateTime.Today;
var lengthValue = lastDay - this.FirstDay;
var builder = new StringBuilder();
var totalDays = (decimal)lengthValue.TotalDays;
var totalYears = totalDays / DaysInAYear;
var years = (int)Math.Floor(totalYears);
totalDays -= (years * DaysInAYear);
var days = (int)Math.Floor(totalDays);
Func<int, string> sIfPlural = value =>
value > 1 ? "s" : string.Empty;
if (years > 0)
{
builder.AppendFormat(
CultureInfo.InvariantCulture,
"{0} year{1}",
years,
sIfPlural(years));
if (days > 0)
{
builder.Append(" ");
}
}
if (days > 0)
{
builder.AppendFormat(
CultureInfo.InvariantCulture,
"{0} day{1}",
days,
sIfPlural(days));
}
var length = builder.ToString();
return length;
}
}
有没有更简洁的方法（但仍然可读）？
答案 0 :(得分：44)
TimeSpan没有“年”的明智概念，因为它取决于起点和终点。 （月份相似 - 29天有多少个月？嗯，这取决于......）
为了给一个无耻的插件，我的Noda Time项目使这个非常简单：
using System;
using NodaTime;
public class Test
{
static void Main(string[] args)
{
LocalDate start = new LocalDate(2010, 6, 19);
LocalDate end = new LocalDate(2013, 4, 11);
Period period = Period.Between(start, end,
PeriodUnits.Years | PeriodUnits.Days);
Console.WriteLine("Between {0} and {1} are {2} years and {3} days",
start, end, period.Years, period.Days);
}
}
输出：
Between 19 June 2010 and 11 April 2013 are 2 years and 296 days
答案 1 :(得分：6)
public string GetAgeText(DateTime birthDate)
{
const double ApproxDaysPerMonth = 30.4375;
const double ApproxDaysPerYear = 365.25;
/*
The above are the average days per month/year over a normal 4 year period
We use these approximations as they are more accurate for the next century or so
After that you may want to switch over to these 400 year approximations
ApproxDaysPerMonth = 30.436875
ApproxDaysPerYear = 365.2425
How to get theese numbers:
The are 365 days in a year, unless it is a leepyear.
Leepyear is every forth year if Year % 4 = 0
unless year % 100 == 1
unless if year % 400 == 0 then it is a leep year.
This gives us 97 leep years in 400 years.
So 400 * 365 + 97 = 146097 days.
146097 / 400 = 365.2425
146097 / 400 / 12 = 30,436875
Due to the nature of the leap year calculation, on this side of the year 2100
you can assume every 4th year is a leap year and use the other approximatiotions
*/
//Calculate the span in days
int iDays = (DateTime.Now - birthDate).Days;
//Calculate years as an integer division
int iYear = (int)(iDays / ApproxDaysPerYear);
//Decrease remaing days
iDays -= (int)(iYear * ApproxDaysPerYear);
//Calculate months as an integer division
int iMonths = (int)(iDays / ApproxDaysPerMonth);
//Decrease remaing days
iDays -= (int)(iMonths * ApproxDaysPerMonth);
//Return the result as an string
return string.Format("{0} years, {1} months, {2} days", iYear, iMonths, iDays);
}
答案 2 :(得分：1)
我不会用TimeSpan来做这件事。一旦超过几天，日期数学就会变得棘手，因为一个月中的天数和一年中的天数不再是恒定的。这可能是TimeSpan不包含Years和Months属性的原因。我会改为确定两个DateTime值之间的年/月/日等数量，并相应地显示结果。
答案 3 :(得分：0)
我认为这应该有效：
public static int DiffYears(DateTime dateValue1, DateTime dateValue2)
{
var intToCompare1 = Convert.ToInt32(dateValue1.ToString("yyyyMMdd"));
var intToCompare2 = Convert.ToInt32(dateValue2.ToString("yyyyMMdd"));
return (intToCompare2 - intToCompare1) / 10000;
}
答案 4 :(得分：0)
Public Function TimeYMDBetween(StartDate As DateTime, EndDate As DateTime) As String
Dim Years As Integer = EndDate.Year - StartDate.Year
Dim Months As Integer = EndDate.Month - StartDate.Month
Dim Days As Integer = EndDate.Day - StartDate.Day
Dim DaysLastMonth As Integer
'figure out how many days were in last month
If EndDate.Month = 1 Then
DaysLastMonth = DateTime.DaysInMonth(EndDate.Year - 1, 12)
Else
DaysLastMonth = DateTime.DaysInMonth(EndDate.Year, EndDate.Month - 1)
End If
'adjust for negative days
If Days < 0 Then
Months = Months - 1
Days = Days + DaysLastMonth 'borrowing from last month
End If
'adjust for negative Months
If Months < 0 Then 'startdate hasn't happend this year yet
Years = Years - 1
Months = Months + 12
End If
Return Years.ToString() + " Years, " + Months.ToString() + " Months and " + Days.ToString() + " Days"
End Function
答案 5 :(得分：0)
我需要针对Core 3执行此操作。NodaTime似乎依赖于Framework 4.7.2。我编写了以下方法，该方法似乎可以将时间跨度格式化为年，月和日，并省略了不需要的部分。
public static string ToYearsMonthsAndDays(this TimeSpan span)
{
var result = string.Empty;
var totalYears = span.Days / 364.25;
var fullYears = Math.Floor(totalYears);
var totalMonths = (span.Days - (365.24 * fullYears)) / 30;
var fullMonths = Math.Floor(totalMonths);
var totalDays = (span.Days - (365.24 * totalYears) - (30 * fullMonths)) / 30;
var fullDays = Math.Floor(totalDays);
var sb = new StringBuilder();
if (fullYears > 0)
{
if (sb.Length > 0)
sb.Append(", ");
sb.Append(fullYears + "y");
}
if (fullMonths > 0)
{
if (sb.Length > 0)
sb.Append(", ");
sb.Append(fullMonths + "m");
}
if (fullDays > 0)
{
if (sb.Length > 0)
sb.Append(", ");
sb.Append(fullDays + "d");
}
return sb.ToString();
}