Calculate relative time in C#

Given a specific DateTime value, how do I display relative time, like:

2 hours ago

3 days ago

a month ago

---

杰夫，你的代码很好，但可以使用常量更清晰（如代码完成所示）。

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 == 1 ? "one second ago" : ts.Seconds + " seconds ago";

if (delta < 2 * MINUTE)
  return "a minute ago";

if (delta < 45 * MINUTE)
  return ts.Minutes + " minutes ago";

if (delta < 90 * MINUTE)
  return "an hour ago";

if (delta < 24 * HOUR)
  return ts.Hours + " hours ago";

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

if (delta < 30 * DAY)
  return ts.Days + " days ago";

if (delta < 12 * MONTH)
{
  int months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));
  return months <= 1 ? "one month ago" : months + " months ago";
}
else
{
  int years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));
  return years <= 1 ? "one year ago" : years + " years ago";
}

---

jquery.timeago plugin

Jeff, because Stack Overflow uses jQuery extensively, I recommend the jquery.timeago plugin.

Benefits:

Avoid timestamps dated "1 minute ago" even though the page was opened 10 minutes ago; timeago refreshes automatically.

You can take full advantage of page and/or fragment caching in your web applications, because the timestamps aren't calculated on the server.

You get to use microformats like the cool kids.

Just attach it to your timestamps on DOM ready:

jQuery(document).ready(function() {
    jQuery('abbr.timeago').timeago();
});

This will turn all abbr elements with a class of timeago and an ISO 8601 timestamp in the title:

<abbr class="timeago" title="2008-07-17T09:24:17Z">July 17, 2008</abbr>

into something like this:

<abbr class="timeago" title="July 17, 2008">4 months ago</abbr>

which yields: 4 months ago. As time passes, the timestamps will automatically update.

Disclaimer: I wrote this plugin, so I'm biased.

---

Here's how I do it

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 < 120)
{
  return "a minute ago";
}
if (delta < 2700) // 45 * 60
{
  return ts.Minutes + " minutes ago";
}
if (delta < 5400) // 90 * 60
{
  return "an hour ago";
}
if (delta < 86400) // 24 * 60 * 60
{
  return ts.Hours + " hours ago";
}
if (delta < 172800) // 48 * 60 * 60
{
  return "yesterday";
}
if (delta < 2592000) // 30 * 24 * 60 * 60
{
  return ts.Days + " days ago";
}
if (delta < 31104000) // 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";

Suggestions? Comments? Ways to improve this algorithm?

链接地址: http://www.djcxy.com/p/4996.html

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