Safely convert UTC datetimes to local time (based on TZ) for calculations?

Posted by James on Stack Overflow See other posts from Stack Overflow or by James
Published on 2010-04-15T17:15:06Z Indexed on 2010/04/15 18:13 UTC
Read the original article Hit count: 266

Filed under:

c#

|

utc

|

datetime

|

datetimeoffset

|

timezone

Following from my last question which @Jon Skeet gave me a lot of help with (thanks again!)

I am now wondering how I can safely work with date/times, stored as UTC, when they are converted back to Local Date/Time.

As Jon indicated in my last question using DateTimeOffset represents an instant in time and there is no way to predict what the local time would be say a minute later. I need to be able to do calculations based on these date/times.

So how can I assure when I pull the dates from the database, convert them to local date/time and do specific calculations on them they are going to be accurate?

© Stack Overflow or respective owner

Related posts about c#

.NET WebRequest.PreAuthenticate not quite what it sounds like

as seen on West-Wind - Search for 'West-Wind'
I’ve run into the problem a few times now: How to pre-authenticate .NET WebRequest calls doing an HTTP call to the server – essentially send authentication credentials on the very first request instead of waiting for a server challenge first? At first glance this sound like it should be easy:… >>> More
HttpWebRequest and Ignoring SSL Certificate Errors

as seen on West-Wind - Search for 'West-Wind'
Man I can't believe this. I'm still mucking around with OFX servers and it drives me absolutely crazy how some these servers are just so unbelievably misconfigured. I've recently hit three different 3 major brokerages which fail HTTP validation with bad or corrupt certificates at least according to… >>> More
The dynamic Type in C# Simplifies COM Member Access from Visual FoxPro

as seen on West-Wind - Search for 'West-Wind'
I’ve written quite a bit about Visual FoxPro interoperating with .NET in the past both for ASP.NET interacting with Visual FoxPro COM objects as well as Visual FoxPro calling into .NET code via COM Interop. COM Interop with Visual FoxPro has a number of problems but one of them at least got a lot… >>> More
Dynamic Type to do away with Reflection

as seen on West-Wind - Search for 'West-Wind'
The dynamic type in C# 4.0 is a welcome addition to the language. One thing I’ve been doing a lot with it is to remove explicit Reflection code that’s often necessary when you ‘dynamically’ need to walk and object hierarchy. In the past I’ve had a number of ReflectionUtils that used string based expressions… >>> More
Finding a Relative Path in .NET

as seen on West-Wind - Search for 'West-Wind'
Here’s a nice and simple path utility that I’ve needed in a number of applications: I need to find a relative path based on a base path. So if I’m working in a folder called c:\temp\templates\ and I want to find a relative path for c:\temp\templates\subdir\test.txt I want to receive back subdir\test… >>> More

Related posts about utc

Why is this giving me 2 different sets of timezones?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi I have this line to get all the timezones Dictionary<string, TimeZoneInfo> storeZoneName = TimeZoneInfo.GetSystemTimeZones().ToDictionary(z => z.DisplayName); Now when I upload I try it on my local machine I get this (UTC-12:00) International Date Line West (UTC-11:00) Coordinated… >>> More
Generating a drop down list of timezones with PHP

as seen on Stack Overflow - Search for 'Stack Overflow'
Most sites need some way to show the dates on the site in the users preferred timezone. Below are two lists that I found and then one method using the built in PHP DateTime class in PHP 5. I need help knowing which of these would be the best to attempt to use when trying to get the UTC offset from… >>> More
MySQL UTC Date format

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi everyone, I am pulling data from Twitter's api and the return date is UTC in the following form: Sat Jan 24 22:14:29 +0000 2009 Can MySQL handle this format specifically or do I need to transform it? I am pulling the data using Python. Thanks, Brock >>> More
Does anyone know how to appropriately deal with user timezones in rails 2.3?

as seen on Stack Overflow - Search for 'Stack Overflow'
We're building a rails app that needs to display dates (and more importantly, calculate them) in multiple timezones. Can anyone point me towards how to work with user timezones in rails 2.3(.5 or .8) The most inclusive article I've seen detailing how user time zones are supposed to work is here:… >>> More
Setting MacBook timezone to UTC

as seen on Super User - Search for 'Super User'
To run my web app, I need to set my timezone to UTC on my MacBook. I can do this temporarily by opening a Konsole and entering sudo ln -sf /usr/share/zoneinfo/UTC /etc/localtime However, my timezone returns to normal when I restart my machine! Any advice? Edit : The response to this question… >>> More