CODEWITHSUNDEEP
c#datetimedatetime-formatwindows-10
Bittercoder
Bittercoder

Reputation: 12143

Output of times (AM/PM) changed in Windows 10 when using DateTime.ToString("tt")

I recently upgraded to windows 10 - and I'm now seeing some rather unexpected changes in the output of a date when using the "tt" format specifier.

Here's some code that demonstrates the issue:

using System.IO;
using System;
using System.Globalization;
using System.Threading.Tasks;

class Program
{
    static void Main()
    {
        var cultures = new string[] {null, "en-NZ", "en-US", "en-AU", "en-GB"};

            foreach (var culture in cultures) {
                if (culture != null) {
                    var c = CultureInfo.GetCultureInfo(culture);
                    System.Threading.Thread.CurrentThread.CurrentCulture = System.Threading.Thread.CurrentThread.CurrentUICulture = c;
                }

                DateTime dt = new DateTime(2015, 1, 2, 3, 4, 5, DateTimeKind.Utc);

                Console.WriteLine("selection: {0} CurrentThread.CurrentCulture.Name: {1} CurrentThread.CurrentUICulture.Name: {2}  Value: {3}",
                    culture ?? "ambient",
                    System.Threading.Thread.CurrentThread.CurrentCulture.Name,
                    System.Threading.Thread.CurrentThread.CurrentUICulture.Name,
                    dt.ToString("hhh:mm tt"));
            }
    }
}

The output in previous versions of windows was:

selection: ambient CurrentThread.CurrentCulture.Name: en-NZ CurrentThread.CurrentUICulture.Name: en-NZ Value: 03:04 a.m.
selection: en-NZ CurrentThread.CurrentCulture.Name: en-NZ CurrentThread.CurrentUICulture.Name: en-NZ Value: 03:04 a.m.
selection: en-US CurrentThread.CurrentCulture.Name: en-US CurrentThread.CurrentUICulture.Name: en-US Value: 03:04 AM
selection: en-AU CurrentThread.CurrentCulture.Name: en-AU CurrentThread.CurrentUICulture.Name: en-AU Value: 03:04 AM
selection: en-GB CurrentThread.CurrentCulture.Name: en-GB CurrentThread.CurrentUICulture.Name: en-GB Value: 03:04 am

And in windows 10:

selection: ambient (windows 10) CurrentThread.CurrentCulture.Name: en-NZ CurrentThread.CurrentUICulture.Name: en-US  Value: 03:04 a.m.
selection: en-NZ CurrentThread.CurrentCulture.Name: en-NZ CurrentThread.CurrentUICulture.Name: en-NZ  Value: 03:04 AM
selection: en-US CurrentThread.CurrentCulture.Name: en-US CurrentThread.CurrentUICulture.Name: en-US  Value: 03:04 AM
selection: en-AU CurrentThread.CurrentCulture.Name: en-AU CurrentThread.CurrentUICulture.Name: en-AU  Value: 03:04 AM
selection: en-GB CurrentThread.CurrentCulture.Name: en-GB CurrentThread.CurrentUICulture.Name: en-GB  Value: 03:04 AM

In both cases this code was compile win Visual Studio 2013 targeting .Net Framework 4.5

Does anyone know why the behavior has changed - and why in windows 10 it appears setting any culture on a thread specifically changes the output of AM/PM to be formatted as "AM" / "PM" not what is normally outputted for that culture?

Upvotes: 14

Views: 1441

Answers (3)

Paul L
Paul L

Reputation: 2260

I also found that the combination of 'en-nz' and Windows 10 upgrade suddenly change a.m./p.m.to AM/PM.

The difference is the code I maintained relaying on ToShortTimeString() output with a.m./p.m. but in Windows 10 it changes to AM/PM instead I spend ages trying to find the correct culture info/format string, and I am also trying to find the missing local setting on my new Windows 10 machine compare to my old Windows 7 machine. But it turns out that the same local setting on different version of Windows machine does indeed display a.m./p.m. AM/PM differently.

Setting on my Windows 10 machine And the AM Symbol changed to AM now Setting on a Windows 7 machine in comparison And the AM Symbol is a.m. for the same Windows display language And same setting on Windows 2012 in comparison which confirm that so far only windows 10 are different

Also confirm that DateTimeFormatInfo.AMDesignator for 'en-nz' now output 'AM' instead of 'a.m.'

Upvotes: 0

XWiśniowiecki
XWiśniowiecki

Reputation: 1843

I always force to use ToString("G") when changing DateTime to string with ToString() function . Then I have no problems to parse the string to DateTime again. I tested it with my client application (gets date & time in XML in "G" format and parses it to DateTime) on Windows 7/8/10.

Upvotes: 0

Shawn Steele - MSFT
Shawn Steele - MSFT

Reputation: 289

You may want to look at "Culture Data Shouldn't Be Considered Stable" http://blogs.msdn.com/b/shawnste/archive/2005/04/05/405694.aspx

One bit is that we started leveraging CLDR (Common Locale Data Repository, http://cldr.unicode.org) for many locales to better align with the industry standards. You may have noticed that there are quite a few additional locales we now have data for.

Upvotes: 6

Related Questions