我不知道为什么会这么复杂！

I don't know why this is so complicated!

我有一个插件，它是传递一个长整型UTC。我需要这个数字转换成的DateTime 来查询我的数据库（SQL Server）。

I have a plugin that is passing in a long int UTC. I need to convert that number into a DateTime to query my database (SQL Server).

我不知道为什么，但我找不到从基本的谷歌搜索一个可行的答案。

I don't know why, but I can't find a workable answer from a basic google search.

（对于额外的学分，我需要把我的返回的DateTime 返回到一个UTC在这一天结束。）

(For extra credit, I need to turn my returned DateTime back into a UTC at the end of the day.)

这是尴尬不得不问这样一个基本问题！ ：）

This is embarrassing to have to ask such a basic question! :)

推荐答案

我的猜测是，这将是无论是毫秒或秒，因为一个特殊的时期 - 1970年1月1日，午夜（UTC）的很可能是Unix纪元

My guess is it's going to be either milliseconds or seconds since a particular epoch - quite possibly the Unix epoch of January 1st 1970, midnight UTC.

所以，code看起来是这样的：

So the code would look something like:

private static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0,
                                                          DateTimeKind.Utc);

public static DateTime FromMillisecondsSinceUnixEpoch(long milliseconds)
{
    return UnixEpoch.AddMilliseconds(milliseconds);
}

请为秒的明显变化，或从不同的时期：）

Make the obvious changes for seconds, or from a different epoch :)

这是另一种方法是创建一个时间跨度自纪元秒/毫秒，然后将其添加到时代：

An alternative approach is to create a TimeSpan of the seconds/milliseconds since the epoch, and then add it to the epoch:

private static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0,
                                                          DateTimeKind.Utc);

public static DateTime FromMillisecondsSinceUnixEpoch(long milliseconds)
{
    return UnixEpoch + TimeSpan.FromMilliseconds(milliseconds);
}

我不知道它们之间的任何显著差异 - 尽管事实上， AddMilliseconds 需要双而不是的长表明，对于非常大的数值，在时间跨度办法可能是preferable。我怀疑它会让任何区别，但：）

I don't know of any significant difference between them - although the fact that AddMilliseconds takes a double instead of a long suggests that for very large values, the TimeSpan approach may be preferable. I doubt that it'll make any difference though :)