method should return DateTime but I want it to return null

[Daves]

a get { ... } for public property SelectedValue returns DateTime type to be
used as a parameter in a Sql update query but I'd like it to return "empty"
if no date has been selected...
I cannot use
return null;

because "Cannot convert null to 'System.DateTime' because it is a value
type"

How can this be done?

 

[Kent Boogaart]

If you're using C# 2 then you can use the Nullable generic type:

public DateTime? SelectedValue
{
get / set;
}

Note the question mark which is short-hand for Nullable<DateTime>. See the
Nullable API doc for more details. If you're using C# 1.0 then you'll need
to either store in a reference type (object) or pick a DateTime to equate to
null (eg. DateTime.MinValue). Alternatively, use an extra bool field to
indicate null.

HTH,
Kent

 

[Vivek]

You can also send the datetime var with out parameter and get the boolean
result like this :

bool Fx(out varDateTime)
{
//return bool;
}
if bool is true, varDateTime is not null

Vivek

Le relais des Artistes (Esvicom - Lieu de Vie, ATBM - Théâtre du Bout des
Mains, DW Home Studio) vous souhaite une très bonne année 2006
http://www.relaisdesartistes.com

 

[Daves]

thx guys, I think I have c# v2, both of your solutions are great.