Question

How do you deal with a DateTime that should be able to contain an uninitialized value (equivalent to null)?

I have a class which might have a DateTime property value set or not. I was thinking of initializing the property holder to DateTime.MinValue, which then could easily be checked.

I’ve been searching a lot but couldn’t find a solution.
I guess this is a quite common question, how do you do that?

Answer 1

For normal DateTimes, if you don’t initialize them at all then they will match DateTime.MinValue, because it is a value type rather than a reference type.

You can also use a nullable DateTime, like this:

DateTime? MyNullableDate; 

Or the longer form:

Nullable<DateTime> MyNullableDate; 

And, finally, there’s a built in way to reference the default of any type. This returns null for reference types, but for our DateTime example it will return the same as DateTime.MinValue:

default(DateTime) 

or, in more recent versions of C#,

default