Empty DateTime Value

  • Thread starter Thread starter Picho
  • Start date Start date
P

Picho

Hi all,

Does anyone know of a GOOD explaination why the DateTime type is a value
time (cannot be null) and furthermore does not provide a DateTime.Empty
value?

when using a DateTimePicker control on windows forms, there is the checkbox
that can indicate an empty date value. there is no such thing for the data
type DateTime.

Picho
 
¤ Hi all,
¤
¤ Does anyone know of a GOOD explaination why the DateTime type is a value
¤ time (cannot be null) and furthermore does not provide a DateTime.Empty
¤ value?
¤
¤ when using a DateTimePicker control on windows forms, there is the checkbox
¤ that can indicate an empty date value. there is no such thing for the data
¤ type DateTime.

Because DateTime objects either contain a value or if unassigned are equal to Nothing.


Paul ~~~ (e-mail address removed)
Microsoft MVP (Visual Basic)
 
Paul Clement said:
Because DateTime objects either contain a value or if unassigned
are equal to Nothing.
Click to expand...

There's no way a DateTime can be equal to Nothing, because Nothing is a
reference value, and DateTime isn't a reference type. If a DateTime
variable is unassigned, it's simply unassigned and (at least in C#) you
can't use it at all - and I'd hope that's true in other languages. If
it weren't, I'd expect the value to be the same as that of
new DateTime().
 
Jon,
There's no way a DateTime can be equal to Nothing, because Nothing is a
reference value, and DateTime isn't a reference type.
Click to expand...

Actually, it can. Nothing, unlike null, is considered equal to the
default value of any type. 0, 0.0, false or null references.



Mattias
 
Mattias Sjögren said:
Actually, it can. Nothing, unlike null, is considered equal to the
default value of any type. 0, 0.0, false or null references.
Click to expand...

Blech. I stand corrected and appalled, both at the same time.
 
Picho said:
Does anyone know of a GOOD explaination why the DateTime type is a value
time (cannot be null) and furthermore does not provide a DateTime.Empty
value?
Click to expand...

You could make the same argument for int. I imagine the answer lies in the
underlying implemenation of the type as a scalar, which is atomically
manipulated at the processor level.

-- Alan
 
Back
Top