Android Question Date/Time to UTC

[ValDog]

I am looking to convert a date/time string, formatted say as "03/07/2015 11:11:44" to UTC format. Can anyone point me in the right direction?

 

[NJDude]

Read the DateTime documentation.

 

[ValDog]

Thanks for responding. Pretty sure I've read that a number of times, and have seen only one unrelated reference to UTC. I'm looking for a bit more direction...

 

[NJDude]

Well, if you read the documentation above, one way of doing it would be setting the time zone to 0, that will give you the UTC time.

 

[Erel]

What exactly do you mean with UTC format? What is the time zone of the date string you wrote?

 

[ValDog]

What exactly do you mean with UTC format? What is the time zone of the date string you wrote?

Time zone I currently wrote in is USA - Eastern, but my application could be in use anywhere in the world - so I need to output the local date/time in UTC.

 

[ac9ts]

This will give you the GMT time for any local time.

lblUTCTime.Text = DateTime.Time(DateTime.Now - DateTime.TicksPerHour * TZOffset)

Public Sub GetTimeZoneOffset As Int
   
    Dim s, d As String
    Dim l As Long
   
    s = DateTime.DateFormat
    DateTime.DateFormat = "MM/dd/yyyy HH:mm:ss"
   
    l = DateTime.Now
    d = DateTime.Date(l) & " GMT"
    DateTime.DateFormat = "MM/dd/yyyy HH:mm:ss z"
   
    Dim res As Int
    res = -Round((l - DateTime.DateParse(d))/3600000)
    DateTime.DateFormat = s
   
    Return res
   
End Sub

 

[ValDog]

This will give you the GMT time for any local time.

lblUTCTime.Text = DateTime.Time(DateTime.Now - DateTime.TicksPerHour * TZOffset)

Public Sub GetTimeZoneOffset As Int
  
    Dim s, d As String
    Dim l As Long
  
    s = DateTime.DateFormat
    DateTime.DateFormat = "MM/dd/yyyy HH:mm:ss"
  
    l = DateTime.Now
    d = DateTime.Date(l) & " GMT"
    DateTime.DateFormat = "MM/dd/yyyy HH:mm:ss z"
  
    Dim res As Int
    res = -Round((l - DateTime.DateParse(d))/3600000)
    DateTime.DateFormat = s
  
    Return res
  
End Sub

Thanks - this is good. I'll be able to use this for real time measurements.

How could I go about converting existing date/time strings (formatted as "03/07/2015 11:11:44") to UTC - given that I know the timezone they were collected in.

 

[ac9ts]

TZoffset is the number of hours from GMT/UTC you are currently based on the timezone setting. Just do some math with the offset.

 

[Erel]

There are several possible ways.

This code adds the EST timezone to the original string and the prints the UTC time:

DateTime.SetTimeZone(0) 'only need to set it once so the process is now based on UTC timezone.
DateTime.DateFormat = "MM/dd/yyyy HH:mm:ss z"
Dim ticks As Long = DateTime.DateParse("03/07/2015 11:11:44" & " EST")
Log(DateTime.Date(ticks))

 

[ValDog]

Thank you all for your help!!!

 

[Troberg]

This will give you the GMT time for any local time.

lblUTCTime.Text = DateTime.Time(DateTime.Now - DateTime.TicksPerHour * TZOffset)

(snip)
    res = -Round((l - DateTime.DateParse(d))/3600000)
(snip)

Just curious, is there any reason you use DateTime.TicksPerHour in one case and 3600000 in the other? Some hidden trap I can't see?

 

[Erel]

Avoid using such date / time arithmetics. Date handling is much more complicated than it may first seem.

You should instead use DateTime and DateUtils API.

 

[ac9ts]

I copied the code with 3600000 from somewhere and wrote the code with DateTime.TicksPerHour. The copied code is in a utilities module that I hardly ever edit (kind of a "Black-Box" chunk of code.