DateTime always displays as UTC

[RickStrahl]

DateTime values always display as UTC time, rather than local time even when explicitly forcing .ToLocalTime().

This:

Console.WriteLine(DateTime.Now.ToLocalTime().ToString("HH:mm"));

displays UTC time.

[Suchiman]

This is a mono issue and should be reported on https://github.com/mono/mono
I was digging around a bit and figured the issue is that emscripten doesn't emulate /etc/localtime and friends, thus mono doesn't know the current timezone and fallbacks to UTC.
You can make it somewhat work by hacking the appropriate offset like this:

var field = typeof(TimeZoneInfo).GetField("local", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic);
field.SetValue(null, TimeZoneInfo.CreateCustomTimeZone("FAKE", TimeSpan.FromHours(2), "FAKE", "FAKE"));

But this doesn't consider DST or adjustment rules.
Newer browsers support zone = new Intl.DateTimeFormat().resolvedOptions().timeZone; to return, for example, Europe/Berlin which you could feed into NodaTime to retrieve the Tzdb timezone which would give you accurate results.

[ransagy]

I have this JS snippet as a workaround but it's not the best thing either:
new Date(new Date().toLocaleString("en-US", { timeZone: Intl.DateTimeFormat().resolvedOptions().timeZone })).getTimezoneOffset() / 60 * -1;

[Andrzej-W]

Tracked here:
mono/mono#6368

[RickStrahl]

Thanks all for clarification.

[jsakamoto]

[FYI] This is my workaround until mono/mono#6368 is fixed.

• https://github.com/jsakamoto/Toolbelt.Blazor.TimeZoneKit