Question

How do I set a null value for an optional DateTime parameter in a constructor?

I’m using the following constructor below and I want the optional parameter admissionDate to be a null DateTime. Setting it to Nothing actually gives it a value (something like #12:00:00 #).

Public Sub New(ByVal obj1 as Object, Optional ByVal admissionDate As DateTime = System.Data.SqlTypes.SqlDateTime.Null) 

Answer 1

I’d suggest using James Curran’s solution but use Overloading instead of an optional parameter, as a workaround for the error you mentioned (‘Optional parameters cannot have structure types’) :

Public Sub New(ByVal obj1 As Object, ByVal admissionDate As Nullable(Of DateTime))   //Your code here End Sub  Public Sub New(Byval obj1 As Object)   Me.New(obj1, Nothing) End Sub 

You can also use DateTime? instead of Nullable(Of DateTime) in the latest version of VB (not sure about the older versions).