DateTime vs DateTimeOffset

Question

Currently, we have a standard way of dealing with .NET DateTime\'s in a TimeZone aware way: Whenever we produce a DateTime we do it in UTC (e.g. us

Answer 1

From Microsoft:

These uses for DateTimeOffset values are much more common than those for DateTime values. As a result, DateTimeOffset should be considered the default date and time type for application development.

_{source: "Choosing Between DateTime, DateTimeOffset, TimeSpan, and TimeZoneInfo", MSDN}

We use DateTimeOffset for nearly everything as our application deals with particular points in time (e.g. when a record was created/updated). As a side note, we use DATETIMEOFFSET in SQL Server 2008 as well.

I see DateTime as being useful when you want to deal with dates only, times only, or deal with either in a generic sense. For example, if you have an alarm that you want to go off every day at 7 am, you could store that in a DateTime utilizing a DateTimeKind of Unspecified because you want it to go off at 7am regardless of DST. But if you want to represent the history of alarm occurrences, you would use DateTimeOffset.

Use caution when using a mix of DateTimeOffset and DateTime especially when assigning and comparing between the types. Also, only compare DateTime instances that are the same DateTimeKind because DateTime ignores timezone offset when comparing.