A DateTime.ToString with CultureInfo("nb-NO") gives the wrong datetime string output on iOS

[sith-ikjetil]

Description

If you compile a .NET MAUI project for iOS, you get the wrong datetime format string for Norwegian output.
If you compile a .NET MAUI project for Windows or Android, you get the correct datetime format string for Norwegian output.

I use dotnet --version 6.0.401

Steps to Reproduce

1. Create a new .NET MAUI APP and compile for iOS.
2. Anywhere like in 'MauiProgram.cs' do something like:
3. var dt = DateTime.Now.ToString( new CultureInfo("nb-NO"));
4. dt will look like: 10/1/2022 4:00:28 PM
5. dt should look like: 01.10.2022 16:00:286

Link to public reproduction project repository

https://github.com/sith-ikjetil/maui-cultureinfo-no-bug

Version with bug

Unknown/Other (please specify)

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

iOS 15.4

Did you find any workaround?

No response

Relevant log output

No response

[drasticactions]

I doubt this is an issue specific with MAUI (The UI Framework) and (probably) more to do with either the runtime or SDK.

@rolfbjarne @dalexsoto Does that sound correct?

[rolfbjarne]

Looks like this could be a duplicate of dotnet/runtime#68321.

@sith-ikjetil can you try printing out the current culture and see what you get?

Console.WriteLine ($"CurrentUICulture: {GetString (Thread.CurrentThread.CurrentUICulture)}");
Console.WriteLine ($"CurrentCulture: {GetString (Thread.CurrentThread.CurrentCulture)}");

static string GetString (CultureInfo ci)
{
	return $"Name: {ci.Name} NativeName: '{ci.NativeName}' DisplayName: '{ci.DisplayName}' EnglishName: '{ci.EnglishName}'";
}

[sith-ikjetil]

CurrentUICulture: Name: nb-US NativeName: 'nb (US)' DisplayName: 'nb (US)' EnglishName: 'nb (US)'
CurrentCulture: Name: nb-US NativeName: 'nb (US)' DisplayName: 'nb (US)' EnglishName: 'nb (US)'

@rolfbjarne This is what i got.

[jfversluis]

This issue was moved to dotnet/macios#16217