I have the following sample code in a VB.NET console application. It compiles and works, but feels like a hack. Is there a way to define EmptyChild so that it inherits from Intermediate(Of T As Class) without using the dummy EmptyClass?
Module Module1
Sub Main()
Dim Child1 = New RealChild()
Child1.Content = New RealClass()
Dim Child2 = New EmptyChild()
Console.WriteLine("RealChild says: " & Child1.Test)
Console.WriteLine("EmptyChild says: " & Child2.Test)
Console.ReadLine()
End Sub
Public Class EmptyClass
End Class
Public Class RealClass
Public Overrides Function ToString() As String
Return "This is the RealClass"
End Function
End Class
Public MustInherit Class Base(Of T As Class)
Private _content As T = Nothing
Public Property Content() As T
Get
Return _content
End Get
Set(ByVal value As T)
_content = value
End Set
End Property
Public Overridable Function Test() As String
If Me._content IsNot Nothing Then
Return Me._content.ToString
Else
Return "Content not initialized."
End If
End Function
End Class
Public MustInherit Class Intermediate(Of T As Class)
Inherits Base(Of T)
'some methods/properties here needed by Child classes
End Class
Public Class RealChild
Inherits Intermediate(Of RealClass)
'This class needs all functionality from Intermediate.
End Class
Public Class EmptyChild
Inherits Intermediate(Of EmptyClass)
'This class needs some functionality from Intermediate,
' but not the Content as T property.
Public Overrides Function Test() As String
Return "We don't care about Content property or Type T here."
End Function
End Class
End Module
The other way to do this would be to move the generic code out of the Base class and then create 2 Intermediate classes like this:
Public MustInherit Class Intermediate
Inherits Base
'some methods/properties here needed by Child classes
End Class
Public MustInherit Class Intermediate(Of T As Class)
Inherits Intermediate
'implement generic Content property here
End Class
Then RealChild would inherit from the generic Intermediate and EmptyChild would inherit from the non-generic Intermediate. My problem with that solution is that the Base class is in a separate assembly and I need to keep the code that handles the generic type in that assembly. And there is functionality in the Intermediate class that does not belong in the assembly with the Base class.