I don't know why this is so complicated!
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).
I don't know why, but I can't find a workable answer from a basic google search.
(For extra credit, I need to turn my returned DateTime back into a UTC at the end of the day.)
This is embarrassing to have to ask such a basic question! :)
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.
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); } Make the obvious changes for seconds, or from a different epoch :)
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); } 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 :)
Is the int you get seconds, milliseconds, or what? After converting it to ticks, (one .NET tick is 100 nanoseconds) e.g. by long ticks = theDBDateNum*TimeSpan.TicksPerMillisecond;, try this:
DateTime theDate = new DateTime(ticks, DateTimeKind.Utc);