How to convert a UTC DateTimeOffset to a DateTime that uses the systems timezone

Question

Quartz.net offers a method to get the next time of the next trigger event: http://quartznet.sourceforge.net/apidoc/1.0/html/html/cc03bb79-c0c4-6d84-3d05-a17f59727c98.htm

The docs claim that this Trigger.GetNextFireTimeUtc() method return a DateTime? but it actually returns a DateTimeOffset?. I don't really get what DateTimeOffset is for or why this function return one instead of a regular DateTime. All I want is the next time the trigger is going to run but in my timezone.

I did this trigger.GetNextFireTimeUtc().Value.DateTime but it gave me a time 2 hours early, i.e. the UTC time. How can I get the correct time according to my computer?

Excruciate

Use the LocalDateTime. You should have a [look][1] [1]: #180440 – Lustrum

You may be interested in DateTime vs DateTimeOffset. – Shizue

Also, you are looking at Quartz's 1.0 docs. Quartz 2.0 changed this method to return a DateTimeOffset?, as shown here. – Shizue

Answer 1

You can just use the DateTimeOffset.LocalDateTime property:

trigger.GetNextFireTimeUtc().Value.LocalDateTime

From the documentation:

If necessary, the LocalDateTime property converts the current DateTimeOffset object's date and time to the local system's date and time. The conversion is a two-step operation:

• The property converts the current DateTimeOffset object's time to Coordinated Universal Time (UTC).
• The property then converts UTC to local time.

You should really look into DateTimeOffset though - it's an important type to understand if you're using the BCL for date/time work.

Ybarra

Why was this answer so hard to find? The M$ Docs on this are evil!!! https://learn.microsoft.com/en-us/dotnet/standard/datetime/converting-between-datetime-and-offset – Leaves

Answer 2

I bumped to this problem and none of these was real answer (by this question title). Solution examples for question title:

var myDateTimeOffset = (DateTimeOffset)DateTime.UtcNow;
var ans1 = myDateTimeOffset.DateTime.ToLocalTime();
var ans2 = myDateTimeOffset.DateTime.ToLocalTime().ToLocalTime(); // ans1==ans2

.NET5 C# 9.0

Moderate

Answer 3

This code is to convert utc to local

var local = utc.ToLocalTime();

Riflery

That's just going to change the DateTime's kind, without changing its value at all. If the OP is simply displaying the value, then they wont see any change – Ybarra

The OP is indeed simply displaying the value – Excruciate