Question

Asp.Net MVC 2 Futures doesn’t seem to handle JSON DateTime well (including double and decimal values). As such, I setup all inputs as string, used Data Validation, and things worked pretty well.

However, I have this JSON2.js date from Firefox 3.6:

"/Date(1288296203190)/"

How do I turn this in to a valid date in C#?

var a = new DateTime(1288296203190);

That doesn’t give the right date (1/2/0001 11:47:09 AM) instead of Thu Oct 28 2010 16:03:23 GMT-0400 (Eastern Daylight Time). It’s probably because a 32 bit integer is only 10 digits. However, this fails too:

var a = Int64.Parse("1288296203190");
var b = new DateTime(a);

b’s value is 1/2/0001 11:47:09 AM.

What did it do? Wrap? Is this some kind of time travel “signed bit” issue?

Answer 1

The issue is the difference in epoch. Looks like the JSON2.js date you have uses the unix epoch (January 1, 1970) measured in ms. From the System.DateTime(long ticks) documenttion:

expects A date and time expressed in the number of 100-nanosecond intervals that have elapsed since January 1, 0001 at 00:00:00.000 in the Gregorian calendar.

Something like this should get you what you want.

var unixEpoch = DateTime(1970, 1, 1);
var ticksSinceEpoch = 1288296203190 * 10000;
var time = new DateTime(unixEpoch.Ticks + ticksSinceEpoch);