Difference between DateTimeOffset?(Nullable) and DateTimeOffset.Now

c# datetime nullable datetimeoffset
nishantvodoo picture nishantvodoo · Jul 31, 2015 · Viewed 11.8k times · Source

How can I calculate the time between between a nullable DateTimeOffset? to DateTimeOffset.Now ?

I need the result like "x day y hours ago"

I started by doing something like this.

  var creationTime = //A nullable DateTimeOffset on Database    
  var difference = DateTimeOffset.Now.Subtract(creationTime);

But since creationTime is a nullable time, it gives me an error and I can't really find the difference.

Answer

Filburt picture Filburt · Jul 31, 2015

Depending on what difference you expect from a NULL database value you can simply handle this using the ?? operator:

DateTimeOffset? creationTime = null; // A nullable DateTimeOffset on Database
DateTimeOffset rightnow = DateTimeOffset.Now;
DateTimeOffset somewhen = creationTime ?? rightnow; // if NULL, it's NOW
var difference = rightnow.Subtract(somewhen);

(could of course be shortend to using ?? just when reading the database value)

Related questions

How can I format a nullable DateTime with ToString()?

How can I convert the nullable DateTime dt2 to a formatted string? DateTime dt = DateTime.Now; Console.WriteLine(dt.ToString("yyyy-MM-dd hh:mm:ss")); //works DateTime? dt2 = DateTime.Now; Console.WriteLine(dt2.ToString("yyyy-MM-dd hh:mm:ss")); //gives following error: …

Read More
How do I use DateTime.TryParse with a Nullable<DateTime>?

I want to use the DateTime.TryParse method to get the datetime value of a string into a Nullable. But when I try this: DateTime? d; bool success = DateTime.TryParse("some date text", out (DateTime)d); the compiler tells me …

Read More
What does "DateTime?" mean in C#?

I am reading a .NET book, and in one of the code examples there is a class definition with this field: private DateTime? startdate What does DateTime? mean?

Read More