C＃DateTime不正确

Question

I have a problem with the difference in getting the time which has arisen this week, possibly due to Daylight Savings Time in the US There is an hour difference in C# and Java (Android). I want the Java to behave the same as the C#.

Windows 10 - C#

value = DateTime.Now;
TimeSpan span = (value - new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime());
System.Diagnostics.Trace.WriteLine("span: " + (int)span.TotalSeconds);

Unix epoch seconds:
1489764265
Which converts to:
Fri, 17 Mar 2017 15:24:25 GMT

Java - Android Studio - Run on Samsung T5330-NU

Date date = new Date(); // current date and time
Integer.toString(ConvertToTimestamp(date))

Unit epoch seconds:
1489760686
Which converts to:
Fri, 17 Mar 2017 14:24:46 GMT

The seconds (:25 vs :46) is fine. The hours are the problem (15 vs 14) Somehow daylight savings time must be involved.

What can be done?

Using this to convert Unix epoch time:
http://www.onlineconversion.com/unix_time.htm

Edit:
Original Java code gets current date/time like so:

Calendar cal = Calendar.getInstance();

Based on the comment by @AkosNagy, I tried:

Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("MST"));

and

Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("MDT"));

but there is no difference.

Edit:
Changed the title because this is in the end a question about C# and why the C# is not giving the correct time.

Edit: This is the line I was looking for:

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

Answer 1

new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime() isn't returning what you think it is. You need to specify the timezone:

new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).ToLocalTime()

1970/1/1 00:00:00.000 in London was actually 1970/1/1 01:00:00.000 UTC (we were in permanent daylight savings at Unix epoch).

---

Or your computer's clock/timezone may be wrong. After all, you posted your code before Fri, 17 Mar 2017 15:24:25 GMT (it was about Fri, 17 Mar 2017 14:40:00 GMT ).

But in any case, it makes the code more robust to specify the UTC timezone, since you won't be dependent upon the local computer's configuration.

Answer 2

(CHECK EDIT BELOW)

In c#, DateTime.Now returns the local time of your computer so time zones don't matter, as you can see in MSDN documentation .

For java, I found these code snippets which use other methods like LocalDateTime.now() .

EDIT:

after reading your answer again, I understood that your problem is with the c# code. that is my solution: instead of that Unix epoch seconds thing:

value = DateTime.Now;
TimeSpan span = (value - new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime());
System.Diagnostics.Trace.WriteLine("span: " + (int)span.TotalSeconds);

just use this:

//first, get the corrent time
DateTime date = DateTime.Now;
//print the time
Console.WriteLine(date.ToString());
// For en-US culture, for other culture type refer to MSDN link
//output mm/dd/yyyy hh:mm:ss AM/pm

If you realy need the Unix epoch seconds, refer to this thread also check your system clock.

Hope I helped!

EDIT: I changed the link to what you needed