鉴于全世界和她的丈夫似乎都在发布代码样本，这是我不久前根据这些答案写的。

我特别需要这个代码可以本地化。所以我有两个类——Grammar，它指定了可本地化的术语，FuzzyDateExtensions，它包含一系列扩展方法。我不需要处理未来的日期时间，因此不尝试使用此代码处理它们。

为了简洁起见，我在源代码中保留了一些XMLdoc，但删除了大部分（显而易见的地方）。我也没有把每个班级成员都包括在这里：

public class Grammar
{
    /// <summary> Gets or sets the term for "just now". </summary>
    public string JustNow { get; set; }
    /// <summary> Gets or sets the term for "X minutes ago". </summary>
    /// <remarks>
    ///     This is a <see cref="String.Format"/> pattern, where <c>{0}</c>
    ///     is the number of minutes.
    /// </remarks>
    public string MinutesAgo { get; set; }
    public string OneHourAgo { get; set; }
    public string HoursAgo { get; set; }
    public string Yesterday { get; set; }
    public string DaysAgo { get; set; }
    public string LastMonth { get; set; }
    public string MonthsAgo { get; set; }
    public string LastYear { get; set; }
    public string YearsAgo { get; set; }
    /// <summary> Gets or sets the term for "ages ago". </summary>
    public string AgesAgo { get; set; }

    /// <summary>
    ///     Gets or sets the threshold beyond which the fuzzy date should be
    ///     considered "ages ago".
    /// </summary>
    public TimeSpan AgesAgoThreshold { get; set; }

    /// <summary>
    ///     Initialises a new <see cref="Grammar"/> instance with the
    ///     specified properties.
    /// </summary>
    private void Initialise(string justNow, string minutesAgo,
        string oneHourAgo, string hoursAgo, string yesterday, string daysAgo,
        string lastMonth, string monthsAgo, string lastYear, string yearsAgo,
        string agesAgo, TimeSpan agesAgoThreshold)
    { ... }
}

FuzzyDateString类包含：

public static class FuzzyDateExtensions
{
    public static string ToFuzzyDateString(this TimeSpan timespan)
    {
        return timespan.ToFuzzyDateString(new Grammar());
    }

    public static string ToFuzzyDateString(this TimeSpan timespan,
        Grammar grammar)
    {
        return GetFuzzyDateString(timespan, grammar);
    }

    public static string ToFuzzyDateString(this DateTime datetime)
    {
        return (DateTime.Now - datetime).ToFuzzyDateString();
    }

    public static string ToFuzzyDateString(this DateTime datetime,
       Grammar grammar)
    {
        return (DateTime.Now - datetime).ToFuzzyDateString(grammar);
    }


    private static string GetFuzzyDateString(TimeSpan timespan,
       Grammar grammar)
    {
        timespan = timespan.Duration();

        if (timespan >= grammar.AgesAgoThreshold)
        {
            return grammar.AgesAgo;
        }

        if (timespan < new TimeSpan(0, 2, 0))    // 2 minutes
        {
            return grammar.JustNow;
        }

        if (timespan < new TimeSpan(1, 0, 0))    // 1 hour
        {
            return String.Format(grammar.MinutesAgo, timespan.Minutes);
        }

        if (timespan < new TimeSpan(1, 55, 0))    // 1 hour 55 minutes
        {
            return grammar.OneHourAgo;
        }

        if (timespan < new TimeSpan(12, 0, 0)    // 12 hours
            && (DateTime.Now - timespan).IsToday())
        {
            return String.Format(grammar.HoursAgo, timespan.RoundedHours());
        }

        if ((DateTime.Now.AddDays(1) - timespan).IsToday())
        {
            return grammar.Yesterday;
        }

        if (timespan < new TimeSpan(32, 0, 0, 0)    // 32 days
            && (DateTime.Now - timespan).IsThisMonth())
        {
            return String.Format(grammar.DaysAgo, timespan.RoundedDays());
        }

        if ((DateTime.Now.AddMonths(1) - timespan).IsThisMonth())
        {
            return grammar.LastMonth;
        }

        if (timespan < new TimeSpan(365, 0, 0, 0, 0)    // 365 days
            && (DateTime.Now - timespan).IsThisYear())
        {
            return String.Format(grammar.MonthsAgo, timespan.RoundedMonths());
        }

        if ((DateTime.Now - timespan).AddYears(1).IsThisYear())
        {
            return grammar.LastYear;
        }

        return String.Format(grammar.YearsAgo, timespan.RoundedYears());
    }
}

我想实现的一件关键事情，以及本地化，就是“今天”只意味着“这个日历日”，所以IsToday、IsThisMonth和IsThisYear方法如下：

public static bool IsToday(this DateTime date)
{
    return date.DayOfYear == DateTime.Now.DayOfYear && date.IsThisYear();
}

舍入方法如下（我已包括RoundedMonths，因为这有点不同）：

public static int RoundedDays(this TimeSpan timespan)
{
    return (timespan.Hours > 12) ? timespan.Days + 1 : timespan.Days;
}

public static int RoundedMonths(this TimeSpan timespan)
{
    DateTime then = DateTime.Now - timespan;

    // Number of partial months elapsed since 1 Jan, AD 1 (DateTime.MinValue)
    int nowMonthYears = DateTime.Now.Year * 12 + DateTime.Now.Month;
    int thenMonthYears = then.Year * 12 + then.Month;                    

    return nowMonthYears - thenMonthYears;
}

我希望人们觉得这很有用和/或有趣：o）

Nuget上还有一个名为Humanizr的软件包，它实际上运行得很好，并且在.NET Foundation中。

DateTime.UtcNow.AddHours(-30).Humanize() => "yesterday"
DateTime.UtcNow.AddHours(-2).Humanize() => "2 hours ago"

DateTime.UtcNow.AddHours(30).Humanize() => "tomorrow"
DateTime.UtcNow.AddHours(2).Humanize() => "2 hours from now"

TimeSpan.FromMilliseconds(1299630020).Humanize() => "2 weeks"
TimeSpan.FromMilliseconds(1299630020).Humanize(3) => "2 weeks, 1 day, 1 hour"

Scott Hanselman在他的博客上写了一篇文章

这是stackoverflow使用的算法，但使用了错误修复（没有“一小时前”）的perlish伪代码进行了更简洁的重写。该函数在秒前取一个（正数），并返回一个人类友好的字符串，如“3小时前”或“昨天”。

agoify($delta)
  local($y, $mo, $d, $h, $m, $s);
  $s = floor($delta);
  if($s<=1)            return "a second ago";
  if($s<60)            return "$s seconds ago";
  $m = floor($s/60);
  if($m==1)            return "a minute ago";
  if($m<45)            return "$m minutes ago";
  $h = floor($m/60);
  if($h==1)            return "an hour ago";
  if($h<24)            return "$h hours ago";
  $d = floor($h/24);
  if($d<2)             return "yesterday";
  if($d<30)            return "$d days ago";
  $mo = floor($d/30);
  if($mo<=1)           return "a month ago";
  $y = floor($mo/12);
  if($y<1)             return "$mo months ago";
  if($y==1)            return "a year ago";
  return "$y years ago";

简单且100%的工作解决方案。

处理过去和将来的时间。。以防万一

        public string GetTimeSince(DateTime postDate)
    {
        string message = "";
        DateTime currentDate = DateTime.Now;
        TimeSpan timegap = currentDate - postDate;

     
        if (timegap.Days > 365)
        {
            message = string.Format(L("Ago") + " {0} " + L("Years"), (((timegap.Days) / 30) / 12));                
        }
        else if (timegap.Days > 30)
        {
            message = string.Format(L("Ago") + " {0} " + L("Months"), timegap.Days/30);                
        }
        else if (timegap.Days > 0)
        {
            message = string.Format(L("Ago") + " {0} " + L("Days"), timegap.Days);
        }           
        else if (timegap.Hours > 0)
        {
            message = string.Format(L("Ago") + " {0} " + L("Hours"), timegap.Hours);
        }           
        else if (timegap.Minutes > 0)
        {
            message = string.Format(L("Ago") + " {0} " + L("Minutes"), timegap.Minutes);
        }
        else if (timegap.Seconds > 0)
        {
            message = string.Format(L("Ago") + " {0} " + L("Seconds"), timegap.Seconds);
        }

        // let's handle future times..just in case       
        else if (timegap.Days < -365)
        {
            message = string.Format(L("In") + " {0} " + L("Years"), (((Math.Abs(timegap.Days)) / 30) / 12));                
        }
        else if (timegap.Days < -30)
        {
            message = string.Format(L("In") + " {0} " + L("Months"), ((Math.Abs(timegap.Days)) / 30));                
        }
        else if (timegap.Days < 0)
        {
            message = string.Format(L("In") + " {0} " + L("Days"), Math.Abs(timegap.Days));                
        }           
      
        else if (timegap.Hours < 0)
        {
            message = string.Format(L("In") + " {0} " + L("Hours"), Math.Abs(timegap.Hours));                
        }
        else if (timegap.Minutes < 0)
        {
            message = string.Format(L("In") + " {0} " + L("Minutes"), Math.Abs(timegap.Minutes));                
        }
        else if (timegap.Seconds < 0)
        {
            message = string.Format(L("In") + " {0} " + L("Seconds"), Math.Abs(timegap.Seconds));                
        }


        else
        {
            message = "a bit";
        }

        return message;
    }

这里是Jeffs Script for PHP的重写：

define("SECOND", 1);
define("MINUTE", 60 * SECOND);
define("HOUR", 60 * MINUTE);
define("DAY", 24 * HOUR);
define("MONTH", 30 * DAY);
function relativeTime($time)
{   
    $delta = time() - $time;

    if ($delta < 1 * MINUTE)
    {
        return $delta == 1 ? "one second ago" : $delta . " seconds ago";
    }
    if ($delta < 2 * MINUTE)
    {
      return "a minute ago";
    }
    if ($delta < 45 * MINUTE)
    {
        return floor($delta / MINUTE) . " minutes ago";
    }
    if ($delta < 90 * MINUTE)
    {
      return "an hour ago";
    }
    if ($delta < 24 * HOUR)
    {
      return floor($delta / HOUR) . " hours ago";
    }
    if ($delta < 48 * HOUR)
    {
      return "yesterday";
    }
    if ($delta < 30 * DAY)
    {
        return floor($delta / DAY) . " days ago";
    }
    if ($delta < 12 * MONTH)
    {
      $months = floor($delta / DAY / 30);
      return $months <= 1 ? "one month ago" : $months . " months ago";
    }
    else
    {
        $years = floor($delta / DAY / 365);
        return $years <= 1 ? "one year ago" : $years . " years ago";
    }
}    

我想我应该用类和多态性来尝试一下。我以前的迭代使用了子类，结果开销太大。我已经切换到一个更灵活的委托/公共属性对象模型，这明显更好。我的代码稍微准确一点，我希望我能想出一种更好的方法来生成“几个月前”的代码，而这种方法看起来并没有过度设计。

我想我还是会坚持Jeff的if-then-cascade，因为它的代码更少，而且更简单（肯定更容易确保它按预期工作）。

对于以下代码，PrintRelativeTime.GetRelativeTime message（TimeSpan ago）返回相对时间消息（例如“昨天”）。

public class RelativeTimeRange : IComparable
{
    public TimeSpan UpperBound { get; set; }

    public delegate string RelativeTimeTextDelegate(TimeSpan timeDelta);

    public RelativeTimeTextDelegate MessageCreator { get; set; }

    public int CompareTo(object obj)
    {
        if (!(obj is RelativeTimeRange))
        {
            return 1;
        }
        // note that this sorts in reverse order to the way you'd expect, 
        // this saves having to reverse a list later
        return (obj as RelativeTimeRange).UpperBound.CompareTo(UpperBound);
    }
}

public class PrintRelativeTime
{
    private static List<RelativeTimeRange> timeRanges;

    static PrintRelativeTime()
    {
        timeRanges = new List<RelativeTimeRange>{
            new RelativeTimeRange
            {
                UpperBound = TimeSpan.FromSeconds(1),
                MessageCreator = (delta) => 
                { return "one second ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = TimeSpan.FromSeconds(60),
                MessageCreator = (delta) => 
                { return delta.Seconds + " seconds ago"; }

            }, 
            new RelativeTimeRange
            {
                UpperBound = TimeSpan.FromMinutes(2),
                MessageCreator = (delta) => 
                { return "one minute ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = TimeSpan.FromMinutes(60),
                MessageCreator = (delta) => 
                { return delta.Minutes + " minutes ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = TimeSpan.FromHours(2),
                MessageCreator = (delta) => 
                { return "one hour ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = TimeSpan.FromHours(24),
                MessageCreator = (delta) => 
                { return delta.Hours + " hours ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = TimeSpan.FromDays(2),
                MessageCreator = (delta) => 
                { return "yesterday"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = DateTime.Now.Subtract(DateTime.Now.AddMonths(-1)),
                MessageCreator = (delta) => 
                { return delta.Days + " days ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = DateTime.Now.Subtract(DateTime.Now.AddMonths(-2)),
                MessageCreator = (delta) => 
                { return "one month ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = DateTime.Now.Subtract(DateTime.Now.AddYears(-1)),
                MessageCreator = (delta) => 
                { return (int)Math.Floor(delta.TotalDays / 30) + " months ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = DateTime.Now.Subtract(DateTime.Now.AddYears(-2)),
                MessageCreator = (delta) => 
                { return "one year ago"; }
            }, 
            new RelativeTimeRange
            {
                UpperBound = TimeSpan.MaxValue,
                MessageCreator = (delta) => 
                { return (int)Math.Floor(delta.TotalDays / 365.24D) + " years ago"; }
            }
        };

        timeRanges.Sort();
    }

    public static string GetRelativeTimeMessage(TimeSpan ago)
    {
        RelativeTimeRange postRelativeDateRange = timeRanges[0];

        foreach (var timeRange in timeRanges)
        {
            if (ago.CompareTo(timeRange.UpperBound) <= 0)
            {
                postRelativeDateRange = timeRange;
            }
        }

        return postRelativeDateRange.MessageCreator(ago);
    }
}