Javascript date to C# via Ajax

Question

I have javascript date object which gives me a date string in this format, "Wed Dec 16 00:00:00 UTC-0400 2009".

I pass this via Ajax to the server (ASP.NET c#)

How can I convert, "Wed Dec 16 00:00:00 UTC-0400 2009" to a C# DateTime object. DateTime.Parse fails.

score 54 · Accepted Answer · answered Dec 09 '09 at 23:58

54

You can use DateTime.ParseExact which allows you to specify a format string to be used for parsing:

DateTime dt = DateTime.ParseExact("Wed Dec 16 00:00:00 UTC-0400 2009",
                                  "ddd MMM d HH:mm:ss UTCzzzzz yyyy",
                                  CultureInfo.InvariantCulture);

answered Dec 09 '09 at 23:58

dtb

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You may want to use DateTimeOffset instead. – ColacX Jun 27 '16 at 08:08

EMP · Answer 2 · 2011-12-12T09:31:10.763

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The most reliable way would be to use milliseconds since the epoch. You can easily get this in JavaScript by calling Date.getTime(). Then, in C# you can convert it to a DateTime like this:

long msSinceEpoch = 1260402952906; // Value from Date.getTime() in JavaScript
return new DateTime(1970, 1, 1).AddTicks(msSinceEpoch * 10000);

You have to multiply by 10,000 to convert from milliseconds to "ticks", which are 100 nanoseconds.

edited Dec 12 '11 at 09:31

answered Dec 10 '09 at 00:03

EMP

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I know this is an old, old answer but I do have a question. Is there any particular reason you add a new TimeSpan instead of calling DateTime's `.AddMilliseconds` method? – Joshua Nov 15 '11 at 17:25
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No reason I can remember. I've edited the answer to use `AddTicks` now, which is probably marginally faster than `AddMilliseconds` (we're talking a few CPU cycles here). – EMP Dec 12 '11 at 09:33
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I got curious about why the "epoch" is 1970/01/01. It turns out this is the "Unix epoch." I thought I'd share in case others are curious or confused: http://en.wikipedia.org/wiki/Unix_time – bopapa_1979 Jun 20 '12 at 16:26
Any reason not to just use DateTime.AddMilliseconds? return new DateTime(1970, 1, 1).AddMilliseconds(msSinceEpoch); – bopapa_1979 Jun 20 '12 at 16:29
I would recommend using Date.parse() in JavaScript (rather than Date.getTime()) - it gets the number of milliseconds since the epoch in local time. – daveywc Sep 27 '12 at 02:44
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Pay attention: JS Date.getTime returns the time in UTC. so if you want local time in C# you have to use ToLocalTime(): `return new DateTime(1970, 1, 1).AddTicks(msSinceEpoch * 10000).ToLocalTime();` – Mahmood Dehghan Oct 31 '16 at 07:20

score 22 · Answer 3 · answered May 06 '14 at 18:58

22

This may not be possible in your case, but I really recommend updating the JS code to pass dates/times in ISO 8601 format. http://en.wikipedia.org/wiki/ISO_8601

ISO 8601 is not only the formal standard, it's also easy to use and prevents a lot of timezone hassle!

To get 8601 datetime strings in Javascript:

var d = new Date();
var iso_time = d.toISOString(); //"2014-05-06T18:49:16.029Z"

To read 8601 datetime strings in C#:

DateTime d = DateTime.Parse(json_string);

answered May 06 '14 at 18:58

Hovis Biddle

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I see this as being the best approach because it's a single step and doesn't require jumping through any other hoops to handle the timezone or System.DateTime parsing. – zomf Apr 08 '15 at 22:45
I'm using this approach to conform to momentjs – Ben Sewards Jun 21 '16 at 19:08

score 5 · Answer 4 · answered Oct 19 '12 at 22:39

Just for posterity, to help future fellow Googlers, I'd like to expand on EMP's answer.

EMP's answer provides the time in UTC (if that's what you're looking for, use that).

To arrive at the client local time in C#:

In JavaScript:

        var now = new Date();
        var UTC = now.getTime();
        var localOffset = (-1) * now.getTimezoneOffset() * 60000;
        var currentTime = Math.round(new Date(UTC + localOffset).getTime());

In C#:

        DateTime currentTimeDotNet = new DateTime(1970, 1, 1).AddTicks(Convert.ToInt64(currentTime) * 10000);

Credit to this blog and EMP's answer, but took some trial and error on both ends to get it right, so just fyi for future folks.

This is the most-correct answer that correctly handles time-zone adjustment. — Dave Jellison, Jan 15 '14 at 13:04

score 0 · Answer 5 · answered Dec 09 '09 at 23:56

To be honest I wouldn't try to parse that date string in C#, I'd personally try to create a more useful date structure from your javascript date object.

For instance you could use parse() in javascript which will return the ms representing the date object, which you can use DateTime.Parse() on to convert into a C# DateTime object.

Javascript date to C# via Ajax

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