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Old April 21st, 2006, 11:56 AM
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Default null values for properties

Hi There,
I was wondering if there are some best practices for handling null value assigments for properties.

For instance, how would I get to following property to accept a null value returned from the database, so I can assign the property value after I instantiated the class?

    Public Property Date_Start() As DateTime Implements Task._Date_Start
            Return _Date_Start
        End Get
        Set(ByVal value As DateTime)
            _Date_Start = value
        End Set
    End Property

'below gets an error in the class method when retrieving the instance
_Date_Start = prmDate_Start.Value

Thanks for your help.

Paul Olofson

Old April 23rd, 2006, 05:33 AM
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Hi there,

.NET 2 has introduced the concepts of a nullable type, allowing you to assign null to a DateTime.


Alternatively, and that's how I often did it in .NET 1.x applications, you can sign it a sensible "nullable in your opinion" default value, like DateTime.MinValue.

Then you can compare against MinValue and it the date is still MinValue you can assume it's null. However, the Nullable type is of course much cleaner.


Imar Spaanjaars
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Author of ASP.NET 2.0 Instant Results and Beginning Dreamweaver MX / MX 2004
While typing this post, I was listening to: The Carnival Is Over by Dead Can Dance (Track 14 from the album: Dead Can Dance 1981-1998 (Limited Edition) [CD2]) What's This?

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