给定特定的DateTime值,如何显示相对时间,例如:

2小时前3天前一个月前


当前回答

通过在客户端执行此逻辑,可以减少服务器端负载。在一些Digg页面上查看源代码以供参考。它们让服务器发出一个由Javascript处理的历元时间值。这样,您就不需要管理最终用户的时区。新的服务器端代码类似于:

public string GetRelativeTime(DateTime timeStamp)
{
    return string.Format("<script>printdate({0});</script>", timeStamp.ToFileTimeUtc());
}

您甚至可以在那里添加一个NOSCRIPT块,然后执行ToString()。

其他回答

您可以使用TimeAgo扩展,如下所示:

public static string TimeAgo(this DateTime dateTime)
{
    string result = string.Empty;
    var timeSpan = DateTime.Now.Subtract(dateTime);
 
    if (timeSpan <= TimeSpan.FromSeconds(60))
    {
        result = string.Format("{0} seconds ago", timeSpan.Seconds);
    }
    else if (timeSpan <= TimeSpan.FromMinutes(60))
    {
        result = timeSpan.Minutes > 1 ? 
            String.Format("about {0} minutes ago", timeSpan.Minutes) :
            "about a minute ago";
    }
    else if (timeSpan <= TimeSpan.FromHours(24))
    {
        result = timeSpan.Hours > 1 ? 
            String.Format("about {0} hours ago", timeSpan.Hours) : 
            "about an hour ago";
    }
    else if (timeSpan <= TimeSpan.FromDays(30))
    {
        result = timeSpan.Days > 1 ? 
            String.Format("about {0} days ago", timeSpan.Days) : 
            "yesterday";
    }
    else if (timeSpan <= TimeSpan.FromDays(365))
    {
        result = timeSpan.Days > 30 ? 
            String.Format("about {0} months ago", timeSpan.Days / 30) : 
            "about a month ago";
    }
    else
    {
        result = timeSpan.Days > 365 ? 
            String.Format("about {0} years ago", timeSpan.Days / 365) : 
            "about a year ago";
    }
 
    return result;
}

或者使用带有Timeago的Razor扩展的jQuery插件。

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";
    }
}    

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)

我是这样做的

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

if (delta < 60)
{
  return ts.Seconds == 1 ? "one second ago" : ts.Seconds + " seconds ago";
}
if (delta < 60 * 2)
{
  return "a minute ago";
}
if (delta < 45 * 60)
{
  return ts.Minutes + " minutes ago";
}
if (delta < 90 * 60)
{
  return "an hour ago";
}
if (delta < 24 * 60 * 60)
{
  return ts.Hours + " hours ago";
}
if (delta < 48 * 60 * 60)
{
  return "yesterday";
}
if (delta < 30 * 24 * 60 * 60)
{
  return ts.Days + " days ago";
}
if (delta < 12 * 30 * 24 * 60 * 60)
{
  int months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));
  return months <= 1 ? "one month ago" : months + " months ago";
}
int years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));
return years <= 1 ? "one year ago" : years + " years ago";

建议?评论?如何改进此算法?

@杰夫

我知道你的有点长。然而,随着对“昨天”和“几年”的支持,它似乎确实更为有力。但根据我的经验,当使用此选项时,用户最有可能在前30天内查看内容。只有真正的铁杆人才会在这之后出现。所以,我通常选择保持简短。

这是我目前在我的一个网站上使用的方法。这只返回相对的日期、小时和时间。然后用户必须在输出中加上“ago”。

public static string ToLongString(this TimeSpan time)
{
    string output = String.Empty;

    if (time.Days > 0)
        output += time.Days + " days ";

    if ((time.Days == 0 || time.Days == 1) && time.Hours > 0)
        output += time.Hours + " hr ";

    if (time.Days == 0 && time.Minutes > 0)
        output += time.Minutes + " min ";

    if (output.Length == 0)
        output += time.Seconds + " sec";

    return output.Trim();
}