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
以某种方式，您可以使用DateTime函数以秒到年计算相对时间，请尝试以下操作：
using System;
public class Program {
public static string getRelativeTime(DateTime past) {
DateTime now = DateTime.Today;
string rt = "";
int time;
string statement = "";
if (past.Second >= now.Second) {
if (past.Second - now.Second == 1) {
rt = "second ago";
}
rt = "seconds ago";
time = past.Second - now.Second;
statement = "" + time;
return (statement + rt);
}
if (past.Minute >= now.Minute) {
if (past.Second - now.Second == 1) {
rt = "second ago";
} else {
rt = "minutes ago";
}
time = past.Minute - now.Minute;
statement = "" + time;
return (statement + rt);
}
// This process will go on until years
}
public static void Main() {
DateTime before = new DateTime(1995, 8, 24);
string date = getRelativeTime(before);
Console.WriteLine("Windows 95 was {0}.", date);
}
}
不完全有效，但如果您对其进行一点修改和调试，它很可能会完成任务。
其他回答
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];
}
}
我也建议在客户端进行计算。服务器工作更少。
以下是我使用的版本（来自Zach Leatherman）
/*
* Javascript Humane Dates
* Copyright (c) 2008 Dean Landolt (deanlandolt.com)
* Re-write by Zach Leatherman (zachleat.com)
*
* Adopted from the John Resig's pretty.js
* at http://ejohn.org/blog/javascript-pretty-date
* and henrah's proposed modification
* at http://ejohn.org/blog/javascript-pretty-date/#comment-297458
*
* Licensed under the MIT license.
*/
function humane_date(date_str){
var time_formats = [
[60, 'just now'],
[90, '1 minute'], // 60*1.5
[3600, 'minutes', 60], // 60*60, 60
[5400, '1 hour'], // 60*60*1.5
[86400, 'hours', 3600], // 60*60*24, 60*60
[129600, '1 day'], // 60*60*24*1.5
[604800, 'days', 86400], // 60*60*24*7, 60*60*24
[907200, '1 week'], // 60*60*24*7*1.5
[2628000, 'weeks', 604800], // 60*60*24*(365/12), 60*60*24*7
[3942000, '1 month'], // 60*60*24*(365/12)*1.5
[31536000, 'months', 2628000], // 60*60*24*365, 60*60*24*(365/12)
[47304000, '1 year'], // 60*60*24*365*1.5
[3153600000, 'years', 31536000], // 60*60*24*365*100, 60*60*24*365
[4730400000, '1 century'] // 60*60*24*365*100*1.5
];
var time = ('' + date_str).replace(/-/g,"/").replace(/[TZ]/g," "),
dt = new Date,
seconds = ((dt - new Date(time) + (dt.getTimezoneOffset() * 60000)) / 1000),
token = ' ago',
i = 0,
format;
if (seconds < 0) {
seconds = Math.abs(seconds);
token = '';
}
while (format = time_formats[i++]) {
if (seconds < format[0]) {
if (format.length == 2) {
return format[1] + (i > 1 ? token : ''); // Conditional so we don't return Just Now Ago
} else {
return Math.round(seconds / format[2]) + ' ' + format[1] + (i > 1 ? token : '');
}
}
}
// overflow for centuries
if(seconds > 4730400000)
return Math.round(seconds / 4730400000) + ' centuries' + token;
return date_str;
};
if(typeof jQuery != 'undefined') {
jQuery.fn.humane_dates = function(){
return this.each(function(){
var date = humane_date(this.title);
if(date && jQuery(this).text() != date) // don't modify the dom if we don't have to
jQuery(this).text(date);
});
};
}
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);
}
}
/**
* {@code date1} has to be earlier than {@code date2}.
*/
public static String relativize(Date date1, Date date2) {
assert date2.getTime() >= date1.getTime();
long duration = date2.getTime() - date1.getTime();
long converted;
if ((converted = TimeUnit.MILLISECONDS.toDays(duration)) > 0) {
return String.format("%d %s ago", converted, converted == 1 ? "day" : "days");
} else if ((converted = TimeUnit.MILLISECONDS.toHours(duration)) > 0) {
return String.format("%d %s ago", converted, converted == 1 ? "hour" : "hours");
} else if ((converted = TimeUnit.MILLISECONDS.toMinutes(duration)) > 0) {
return String.format("%d %s ago", converted, converted == 1 ? "minute" : "minutes");
} else if ((converted = TimeUnit.MILLISECONDS.toSeconds(duration)) > 0) {
return String.format("%d %s ago", converted, converted == 1 ? "second" : "seconds");
} else {
return "just now";
}
}
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。
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