Convert current date and time into timestamp object (13 digits)

Question

The following is the code for converting java datestamp (13digits) to date (1520488577604 to 3/12/2018 8:07:02 PM) in C#.

new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)
    .AddMilliseconds((long)value) // put your value here
    .ToLocalTime().ToString("g");

I need to reverse this feature, need to convert from 3/12/2018 8:07:02 PM to 1520488577604.

check answer below. Let me know if you need anything more in it — Gaurang Dave, Mar 13 '18 at 05:31
This is a classic UnixTimestamp https://stackoverflow.com/questions/17632584/how-to-get-the-unix-timestamp-in-c-sharp — Gavin Stevens, Mar 13 '18 at 06:04
Are you sure about the exact values? 1520488577604 should be somewhere around 2018/03/08 05:56:17+0000 — Paul Kertscher, Mar 13 '18 at 06:31

score 9 · Accepted Answer · edited Mar 13 '18 at 07:24

9

Though Gavin and Gaurang are pretty close, they missed a detail: You wanted the total milliseconds from 1970/01/01

namespace MyApp.Extensions
{
    public static class DateTimeExtensions
    {
        public static long MillisecondsTimestamp(this DateTime date)
        {
            DateTime baseDate = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
            return (long)(date.ToUniversalTime()-baseDate).TotalMilliseconds;
        }
    }
}

You can use it like

using MyApp.Extensions;

// ...
var millisecondsTimestamp = DateTime.Now.MillisecondsTimestamp();

given that you've added the namespace the DateTimeExtensions is located in.

edited Mar 13 '18 at 07:24

Sreejith Sree

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answered Mar 13 '18 at 06:14

Paul Kertscher

9,416
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thanks for drawing my attention. – Gaurang Dave Mar 13 '18 at 06:20
@GaurangDave What exactly do you mean? – Paul Kertscher Mar 13 '18 at 06:32
to use TotalMilliseconds. – Gaurang Dave Mar 13 '18 at 06:33
@GaurangDave Ah, got it. I thought that it would've been clear from the comments to your answer :) – Paul Kertscher Mar 13 '18 at 06:35
You mentioned my name in your answer then I saw comments and got my mistake. Anyway thanks :) – Gaurang Dave Mar 13 '18 at 06:36
'DateTime' does not contain a definition for 'MillisecondsTimestamp' and no extension method 'MillisecondsTimestamp' accepting a first argument of type 'DateTime' could be found (are you missing a using directive or an assembly reference?) – Sreejith Sree Mar 13 '18 at 06:36
Did you put `MillisecondsTimestamp` in a static class? Is the namespace included? – Paul Kertscher Mar 13 '18 at 06:38
@SreejithSree Please see my edit. – Paul Kertscher Mar 13 '18 at 06:39
I Add class keyword for DateTimeExtensions – Sreejith Sree Mar 13 '18 at 06:58

Gaurang Dave · Answer 2 · 2018-03-13T06:21:37.273

3

Try this :

10 digits:

public static long ConvertToTS(DateTime datetime)
{
    DateTime sTime = new DateTime(1970, 1, 1,0,0,0,DateTimeKind.Utc);

    return (long)(datetime - sTime).TotalSeconds;
}

13 digits:

public static long ConvertToTS(DateTime datetime)
{
    DateTime sTime = new DateTime(1970, 1, 1,0,0,0,DateTimeKind.Utc);

    return (long)(datetime - sTime).TotalMilliseconds;
}

edited Mar 13 '18 at 06:21

answered Mar 13 '18 at 05:29

Gaurang Dave

3,956
2
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1

The output of this function is a 10 digit number(1520939407),I need a 13 digit number. I am calling this function like this: ConvertToTS(DateTime.Now) and date stored in db is 2031-01-12 18:18:11.421 – Sreejith Sree Mar 13 '18 at 05:45
why down vote? are yo getting 1520939407 this for 2031-01-12 18:18:11.421 ? – Gaurang Dave Mar 13 '18 at 06:14
I am not put downvote, someone else do that – Sreejith Sree Mar 13 '18 at 06:14
I downvoted. As the asker stated, he needs the full 13 digits, you're giving him 10. – Anthony Pegram Mar 13 '18 at 06:15
@AnthonyPegram I edited. And if possible, wait for final conclusion. I will also take care. remove down vote if possible. – Gaurang Dave Mar 13 '18 at 06:17
@SreejithSree check update – Gaurang Dave Mar 13 '18 at 06:17
2

The downvote prompted you to improve your answer, it served its purpose. I'll not wait, thanks. Though I did remove it once updated. – Anthony Pegram Mar 13 '18 at 06:18
This gives wrong values unless `datetime` is in UTC anyway. – Paul Kertscher Mar 13 '18 at 06:29

score 1 · Answer 3 · answered Mar 13 '18 at 06:04

1

Int32 unixTimestamp = (Int32)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalSeconds;

How to get the unix timestamp in C#

answered Mar 13 '18 at 06:04

Gavin Stevens

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14

Getting a 10 dig long value, for me need a 13 digit timestamp – Sreejith Sree Mar 13 '18 at 06:11
The last 3 digits are milliseconds, do they really matter.. – Gavin Stevens Mar 13 '18 at 06:13
Int32 unixTimestamp = (Int32)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalMilliseconds; – Gavin Stevens Mar 13 '18 at 06:14
@Gavin, yes? The requirement is to take 13 digits, get to a date, and then get the 13 digits back as entered. – Anthony Pegram Mar 13 '18 at 06:14
1

Double unixTimestamp = (Double)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalMilliseconds; – Gavin Stevens May 04 '18 at 23:19
Gives you 13 digits, plus a fraction... – Gavin Stevens May 04 '18 at 23:20

Convert current date and time into timestamp object (13 digits)

3 Answers3

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