这是我的功能，就像一个魅力：）

public static string RelativeDate(DateTime theDate)
{
   var span = DateTime.Now - theDate;
   if (span.Days > 365)
   {
      var years = (span.Days / 365);
      if (span.Days % 365 != 0)
         years += 1;
      return $"about {years} {(years == 1 ? "year" : "years")} ago";
   }
   if (span.Days > 30)
   {
      var months = (span.Days / 30);
      if (span.Days % 31 != 0)
         months += 1;
      return $"about {months} {(months == 1 ? "month" : "months")} ago";
   }
   if (span.Days > 0)
      return $"about {span.Days} {(span.Days == 1 ? "day" : "days")} ago";
   if (span.Hours > 0)
      return $"about {span.Hours} {(span.Hours == 1 ? "hour" : "hours")} ago";
   if (span.Minutes > 0)
      return $"about {span.Minutes} {(span.Minutes == 1 ? "minute" : "minutes")} ago";
   if (span.Seconds > 5)
      return $"about {span.Seconds} seconds ago";

   return span.Seconds <= 5 ? "about 5 seconds ago" : string.Empty;
}

我将为此提供一些方便的扩展方法，并使代码更可读。首先，Int32的两个扩展方法。

public static class TimeSpanExtensions {

    public static TimeSpan Days(this int value) {

        return new TimeSpan(value, 0, 0, 0);
    }

    public static TimeSpan Hours(this int value) {

        return new TimeSpan(0, value, 0, 0);
    }

    public static TimeSpan Minutes(this int value) {

        return new TimeSpan(0, 0, value, 0);
    }

    public static TimeSpan Seconds(this int value) {

        return new TimeSpan(0, 0, 0, value);
    }

    public static TimeSpan Milliseconds(this int value) {

        return new TimeSpan(0, 0, 0, 0, value);
    }

    public static DateTime Ago(this TimeSpan value) {

        return DateTime.Now - value;
    }
}

然后，为DateTime设置一个。

public static class DateTimeExtensions {

    public static DateTime Ago(this DateTime dateTime, TimeSpan delta) {

        return dateTime - delta;
    }
}

现在，您可以执行以下操作：

var date = DateTime.Now;
date.Ago(2.Days()); // 2 days ago
date.Ago(7.Hours()); // 7 hours ago
date.Ago(567.Milliseconds()); // 567 milliseconds ago

var ts = new TimeSpan(DateTime.Now.Ticks - dt.Ticks);

public static string ToRelativeDate(DateTime input)
{
    TimeSpan oSpan = DateTime.Now.Subtract(input);
    double TotalMinutes = oSpan.TotalMinutes;
    string Suffix = " ago";

    if (TotalMinutes < 0.0)
    {
        TotalMinutes = Math.Abs(TotalMinutes);
        Suffix = " from now";
    }

    var aValue = new SortedList<double, Func<string>>();
    aValue.Add(0.75, () => "less than a minute");
    aValue.Add(1.5, () => "about a minute");
    aValue.Add(45, () => string.Format("{0} minutes", Math.Round(TotalMinutes)));
    aValue.Add(90, () => "about an hour");
    aValue.Add(1440, () => string.Format("about {0} hours", Math.Round(Math.Abs(oSpan.TotalHours)))); // 60 * 24
    aValue.Add(2880, () => "a day"); // 60 * 48
    aValue.Add(43200, () => string.Format("{0} days", Math.Floor(Math.Abs(oSpan.TotalDays)))); // 60 * 24 * 30
    aValue.Add(86400, () => "about a month"); // 60 * 24 * 60
    aValue.Add(525600, () => string.Format("{0} months", Math.Floor(Math.Abs(oSpan.TotalDays / 30)))); // 60 * 24 * 365 
    aValue.Add(1051200, () => "about a year"); // 60 * 24 * 365 * 2
    aValue.Add(double.MaxValue, () => string.Format("{0} years", Math.Floor(Math.Abs(oSpan.TotalDays / 365))));

    return aValue.First(n => TotalMinutes < n.Key).Value.Invoke() + Suffix;
}

http://refactormycode.com/codes/493-twitter-esque-relative-dates

C#6版本：

static readonly SortedList<double, Func<TimeSpan, string>> offsets = 
   new SortedList<double, Func<TimeSpan, string>>
{
    { 0.75, _ => "less than a minute"},
    { 1.5, _ => "about a minute"},
    { 45, x => $"{x.TotalMinutes:F0} minutes"},
    { 90, x => "about an hour"},
    { 1440, x => $"about {x.TotalHours:F0} hours"},
    { 2880, x => "a day"},
    { 43200, x => $"{x.TotalDays:F0} days"},
    { 86400, x => "about a month"},
    { 525600, x => $"{x.TotalDays / 30:F0} months"},
    { 1051200, x => "about a year"},
    { double.MaxValue, x => $"{x.TotalDays / 365:F0} years"}
};

public static string ToRelativeDate(this DateTime input)
{
    TimeSpan x = DateTime.Now - input;
    string Suffix = x.TotalMinutes > 0 ? " ago" : " from now";
    x = new TimeSpan(Math.Abs(x.Ticks));
    return offsets.First(n => x.TotalMinutes < n.Key).Value(x) + Suffix;
}

文斯回答的土耳其语本地化版本。

    const int SECOND = 1;
    const int MINUTE = 60 * SECOND;
    const int HOUR = 60 * MINUTE;
    const int DAY = 24 * HOUR;
    const int MONTH = 30 * DAY;

    var ts = new TimeSpan(DateTime.UtcNow.Ticks - yourDate.Ticks);
    double delta = Math.Abs(ts.TotalSeconds);

    if (delta < 1 * MINUTE)
        return ts.Seconds + " saniye önce";

    if (delta < 45 * MINUTE)
        return ts.Minutes + " dakika önce";

    if (delta < 24 * HOUR)
        return ts.Hours + " saat önce";

    if (delta < 48 * HOUR)
        return "dün";

    if (delta < 30 * DAY)
        return ts.Days + " gün önce";

    if (delta < 12 * MONTH)
    {
        int months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));
        return months + " ay önce";
    }
    else
    {
        int years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));
        return years + " yıl önce";
    }

iPhone Objective-C版本

+ (NSString *)timeAgoString:(NSDate *)date {
    int delta = -(int)[date timeIntervalSinceNow];

    if (delta < 60)
    {
        return delta == 1 ? @"one second ago" : [NSString stringWithFormat:@"%i seconds ago", delta];
    }
    if (delta < 120)
    {
        return @"a minute ago";
    }
    if (delta < 2700)
    {
        return [NSString stringWithFormat:@"%i minutes ago", delta/60];
    }
    if (delta < 5400)
    {
        return @"an hour ago";
    }
    if (delta < 24 * 3600)
    {
        return [NSString stringWithFormat:@"%i hours ago", delta/3600];
    }
    if (delta < 48 * 3600)
    {
        return @"yesterday";
    }
    if (delta < 30 * 24 * 3600)
    {
        return [NSString stringWithFormat:@"%i days ago", delta/(24*3600)];
    }
    if (delta < 12 * 30 * 24 * 3600)
    {
        int months = delta/(30*24*3600);
        return months <= 1 ? @"one month ago" : [NSString stringWithFormat:@"%i months ago", months];
    }
    else
    {
        int years = delta/(12*30*24*3600);
        return years <= 1 ? @"one year ago" : [NSString stringWithFormat:@"%i years ago", years];
    }
}