Is it possible to specify a return type of "Derivative(of T)" for a MustOverride sub in VB.NET?
- by Casey
VB.NET 2008 .NET 3.5
I have two base classes that are MustInherit (partial). Let's call one class OrderBase and the other OrderItemBase.
A specific type of order and order item would inherit from these classes. Let's call these WebOrder (inherits from OrderBase) and WebOrderItem (inherits from OrderItemBase).
Now, in the grand scheme of things WebOrder is a composite class containing a WebOrderItem, like so:
Public Class WebOrder
Inherits OrderBase
Public Property OrderItem() as WebOrderItem
End Property
End Class
Public Class WebOrderItem
Inherits OrderItemBase
End Class
In order to make sure any class that derives from OrderBase has the OrderItem property, I would like to do something like this in the OrderBase class:
Public MustInherit Class OrderBase
Public MustOverride Property OrderItem() as Derivative(Of OrderItemBase)
End Class
In other words, I want the derived class to be forced to contain a property that returns a derivative of OrderItemBase.
Is this possible, or should I be using an entirely different approach?
