comparing nullables

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

What is the recommended way for comparing two nullabe DateTime types using
the CompareTo method.

DateTime? d1
DateTime? d2

return d1.Value.CompareTo(d2.Value) //This obvoiusly will fail if one is null

return d1.GetDefaultOrValue().CompareTo(d2.GetDefaultOrValue()) //this works
but it is a hack as you are converting a null type to DateTime.MinValue and
then doing a compare.

I wish to return
-1 if d1 < d2,
0 if d1 = d2,
1 if d1 > d2

Thanks
 
In many classes Compare is often implemented as a static method for null
behaviour. I see a static DateTime.Compare(t1,t2) method, but I have not
tried
it.

Regards,
Jeff
 
STech,

You can always use the static Compare<T> method on the Nullable class,
like so:

DateTime? d1;
DateTime? d2;

return Nullable.Compare(d1, d2);

Hope this helps.
 
Hi,
Welcome to MSDN Newsgroup!

We could write one method to compare the DateTime. At .Net 2.0, the
Nullable structure could be used for this scenario. The parameter type of
this method could be DateTime?.
//-------------------------------
static int CompareDT(DateTime? dt1, DateTime? dt2)
{
if (dt1.HasValue && dt2.HasValue)
return dt1.Value.CompareTo(dt2.Value);
else
return -2; //custom error code
}
//----------------------------------
If dt1 or dt2 is a null value, we should return error code, which assured
that there's no exception will be thrown and this snippet code will always
work.

I hope the above information is useful for you. If you have any questions
or concerns, please feel free to let me know. :)

Best Regards,

Terry Fei[MSFT]
Microsoft Community Support
Get Secure! www.microsoft.com/security
(This posting is provided "AS IS", with no warranties, and confers no
rights.)
 
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