Shadowing using Shadows in Visual Basic.NET 2005 - Using Shadows with methods in Visual Basic 2005

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In previous sections, I discussed both fields and properties using "shadows."  "Shadows" are not limited to "Fields" and "Properties;" they can also be used for "methods."  Now I'm extending  the discussion to "methods."

Consider the following code before we proceed:

Public Class Parent

 

  Public Sub DispMsg()

    MessageBox.Show("From Parent")

  End Sub

 

End Class

 

Public Class Child

  Inherits Parent

 

  Public Shadows Sub DispMsg()

    MessageBox.Show("From child")

  End Sub

 

End Class

In the above two classes, there exists the same method, "DispMsg," with the same signature (which may have different implementations). Thus we need "shadows."

We can test the above classes using the following style of code:

    Dim objParent As New Parent

    Dim objChild As New Child

 

    objParent.DispMsg()

    objChild.DispMsg()

And finally, using a parent reference, we can test as follows (which displays "From Parent"):

    Dim RefParent As Parent = objChild

    RefParent.DispMsg()

We can even access a parent member without creating a separate reference variable as follows:

    CType(objChild, Parent).DispMsg()

The above applies even to shadowed "fields" and "properties."

Next: Using Shadows with overloaded parent methods in Visual Basic 2005 >>
 

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