Question

Consider the following example:

Public Class ParentClass
    Public Sub GenerateReport
        Dim Col As Collection
        Col = GetItemCollection()
    End Sub

    Public Overridable Function GetItemCollection() As Collection
        GetItemCollection = New Collection
        GetItemCollection.Add("1")
        GetItemCollection.Add("2")
        GetItemCollection.Add("3")
    End Function
End Class

Public Class ExtendedClass
    Inherits ParentClass

    Public Overrides Function GetItemCollection() As Collection
        GetItemCollection = New Collection
        GetItemCollection.Add("A")
        GetItemCollection.Add("B")
        GetItemCollection.Add("C")
    End Function
End Class

Public Sub Main()
    Dim cls As New ExtendedClass
    cls.GenerateReport()
End Sub

When Main() calls cls.GenerateReport(), is the variable Col going to be a collection of numbers or letters? I’m hoping that it will recognize that cls is an instance of ExtendedClass and call the overridden method and return the letters.

Answer 1

It will be a collection of letters as you did override the method. However, where did you declare the GetItemCollection? You still need an instance variable.