ToUniversalTime strange behavior

Question

Hi. ToUniversalTime() returns incorrect DateTime for (2013, 3, 17, 1, 0, 0).

see my code:

 //d1 is less than d2 how ever after converting to utc
            //resault is strange and d1Utc is greater than d2Utc
            DateTime d1 = new DateTime(2013, 3, 17, 0, 45, 0);
            DateTime d2 = new DateTime(2013, 3, 17, 1, 0, 0);
            
            var d1Utc = d1.ToUniversalTime();
            var d2Utc = d2.ToUniversalTime();

            Console.WriteLine(d1Utc.ToString());  //3/16/2013 9:15:00 PM
            Console.WriteLine(d2Utc.ToString());  //3/16/2013 8:30:00 PM

Tanks in advance

Answer 1

What timezone are you in and when's daylight saving kicking in for you?

Check out: http://msdn.microsoft.com/en-us/library/bb396403.aspx to see if the DateTime value you have is Ambiguous in your timezone (might explain the 1hr skew)

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My blog: blog.jessehouwing.nl

Answer 2

Hi Jesse,  My PC time zone is Iran +3:30 GMT.

I'll check it tomorrow and post results here.

tanks again.

Answer 3

Hi. Jesse.

            TimeZoneInfo iranZone = TimeZoneInfo.FindSystemTimeZoneById("Iran Standard Time");

            Console.WriteLine(iranZone.IsAmbiguousTime(d1));  // false
            Console.WriteLine(iranZone.IsAmbiguousTime(d2));  // false

I've checked both dates above. they are InAmbigoues!!

Now I'm wondering where is the problem?

Tanks.

Answer 4

It beats me :). Given a date in the second or third week of March chances where high Daylight Savings had something to do with it...

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My blog: blog.jessehouwing.nl

Answer 5

I have connected the Microsoft Connect Site to help you submit a feedback.

Link at here:

https://connect.microsoft.com/VisualStudio/feedback/details/729627/iran-time-to-touniversaltime-strange-behavior

For now, We are doing some research of this issue and will get back to you once we have any update information.

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Best Regards,
Rocky Yue[MSFT]
MSDN Community Support | Feedback to us

Answer 6

As I double checked, I found that 2013, 3, 17, 1, 0, 0 is in daylight saving time range for the Iran +3:30 GMT time zone.

http://msdn.microsoft.com/en-us/library/system.datetime.isdaylightsavingtime.aspx 

So we need handle it like the below code for your reference:

    if (d2.IsDaylightSavingTime())
            {
                var d2Utc = d2.ToUniversalTime().AddHours(1);
            }

Hope it helps.

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Best Regards,
Rocky Yue[MSFT]
MSDN Community Support | Feedback to us

Answer 7

Tanks Mr. Rocky Yue. your solution is right.

Answer 8

You are welcome.

It's my pleasure to help you.

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Best Regards,
Rocky Yue[MSFT]
MSDN Community Support | Feedback to us