How do I store a negative TimeSpan in Entity Framework?

Question

Hi all;

I store shifts to events with a TimeSpan as the offset from the start of the event and another TimeSpan as the duration of the shift. The setup shift starts before the event (so everyone see the event as 11:00am - 4:00pm as desired while the setup shift starts at 10:15am).

Entity Framework throws an exception saving a TimeSpan < 0 or >= 24:00:00. Is there a way to save a TimeSpan outside the 0 .. 24 hour range?

thanks - dave

Answer 1

Your issue is the default mapping of TimeSpan is to sql Time, which is a time, not a time period. But EF supports mapping a TimeSpan to a long, and will convert the TimeSpan to ticks, which is a period and can be negative.

https://learn.microsoft.com/en-us/ef/core/modeling/value-conversions?tabs=data-annotations