DateTime, TimeZone, AAARRRRRGGGGGGGGHHHHHHHH!

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David Thielen - 27 Oct 2006 00:51 GMT

Hi;

Ok, I'm going nuts here. We have a scheduler in our ASP.NET app and here are
a couple of major problems I am hitting.

1) Someone schedules an item to run weekdays at 1:00 am - Colorado time. The
server is in Japan so it's the next day there for local server time. Or the
local & server could be such that it is a different day UTC time.

The easy approach seems to be that I set the scheduled time to run next in
UTC - but I save the time of day to run in the timezone of the request and do
my calculations of the next run in the requesters time zone so I am working
in the datetime that will be correct for IsWeekday, etc.

Here's the problem - how can I get a DateTime for a timezone that is not UTC
and not server local? Those seem to be the only two choices.

2) Based on a user's Culture - how do I determine what days are the weekend?
GetDayOfWeek returns a 0 for Sunday regardless of culture. But the weekend in
the Middle East is Friday/Saturday while it's Saturday/Sunday everywhere else
(I think).

3) Based on a user's culture, how do I find out the first day of the week?
In the US it's Sunday while I believe in Europe it's Monday. And who knows
what elsewhere.

4) Where can I get the localized (by culture) names for months of the year
and days of the month?

Signature

thanks - dave
david_at_windward_dot_net
http://www.windwardreports.com

Cubicle Wars - http://www.windwardreports.com/film.htm

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Steven Cheng[MSFT] - 27 Oct 2006 09:27 GMT

Hello Dave,

As for the DateTime and TimeZone issue, I think it will be hard to
completely handled through the .net framework interfaces. Yes, you're
limited to current timezone and UTC time when using the Datetime functions
to manipulate DateTime instances.

For your scenario, is it posible that you always converted DateTime to a
consistent timezone(of the server's local timezone) before store them in
system. And all the calculation will based on only one timezone?

For get datetime of non-local or UTC zone, so far there is no built-in
support in .net framework. What we can do is get the timezone offset (you
can find some information in your another several posts) and do the
calculation to get other timezone's datetime.

For your following questions:

=======================
2) Based on a user's Culture - how do I determine what days are the
weekend?
GetDayOfWeek returns a 0 for Sunday regardless of culture. But the weekend
in
the Middle East is Friday/Saturday while it's Saturday/Sunday everywhere
else
(I think).

3) Based on a user's culture, how do I find out the first day of the week?
In the US it's Sunday while I believe in Europe it's Monday. And who knows
what elsewhere.
========================

So far I haven't got any good ideas, I can help you ask some other
globaldev engineers to see whether there is any means through win32
platform API. The .net encapsulated interfaces are all under the
System.Globalization namespace(especially the XXXCalender class).

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead

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David Thielen - 27 Oct 2006 16:17 GMT

ok - thanks.

It still astounds me how incomplete I18N support is to this day.

Signature

thanks - dave
david_at_windward_dot_net
http://www.windwardreports.com

Cubicle Wars - http://www.windwardreports.com/film.htm

> Hello Dave,
>
[quoted text clipped - 66 lines]
>
> This posting is provided "AS IS" with no warranties, and confers no rights.

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David Thielen - 27 Oct 2006 16:18 GMT

Hi again;

Any idea on:
4) Where can I get the localized (by culture) names for months of the year
and days of the month?

Signature

thanks - dave
david_at_windward_dot_net
http://www.windwardreports.com

Cubicle Wars - http://www.windwardreports.com/film.htm

Reply to this Message

David Thielen - 27 Oct 2006 16:23 GMT

Found this one - DateTimeFormatInfo

Signature

thanks - dave
david_at_windward_dot_net
http://www.windwardreports.com

Cubicle Wars - http://www.windwardreports.com/film.htm

> Hi again;
>
> Any idea on:
> 4) Where can I get the localized (by culture) names for months of the year
> and days of the month?

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Steven Cheng[MSFT] - 30 Oct 2006 11:00 GMT

Thanks for your reply Dave,

I've consult some other globaldev engineers and here are some further
information:

The following two posts have the explanation of what can be returned about
weeks and weekends what cannot, and why

http://blogs.msdn.com/michkap/archive/2006/08/24/710624.aspx
http://blogs.msdn.com/michkap/archive/2005/09/20/471605.aspx

here is the original comments from them:
===================
As for the Gregorian localized names, they are only available when you have
the appropriate UI language installed; other calendars that have their own
day names will sometimes find themselves already localized within the
calendar.

In other words, most of this info is not generically available to any
application....
====================

Hope this helps further.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead

This posting is provided "AS IS" with no warranties, and confers no rights.

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DateTime, TimeZone, AAARRRRRGGGGGGGGHHHHHHHH!

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