How to Re-Implement interfaces in VB.NET

In this article you will learn how to re-implement interfaces in VB.NET
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Suppose we have an interface implemented on a class and we want to create a subclass derived from the super class and change the implementation. The difference between the way of re-implementation is that in VB.NET you can not implement an interface on a subclass of a superclass that has already implemented it whereas In C# you can. Instead of implementing the interface a second time, you can override the superclass method that implements the interface method. Here I will explain how to re-implement interfaces in VB.NET, code is given below so you can take a first look:

Module Module1
    Class BaseClass
        Implements IFormattable
        Implements IComparable 
        Public Value As String
        Public Overridable Overloads Function ToString(ByVal _
          Format As String, ByVal Provider As IFormatProvider) _
          As String Implements IFormattable.ToString
             ToString = Value
        End Function
        Public Overridable Overloads Function CompareTo(ByVal A _
          As Object) As Integer Implements IComparable.CompareTo
            If (Value = A.Value) Then
                CompareTo = 0
            ElseIf (Value < A.Value) Then
                CompareTo = -1
            Else
                CompareTo = 1
            End If
        End Function
        Public Sub New(ByVal Value As String)
            Me.Value = Value
        End Sub
   End Class

   Class DerivedClass
       Inherits BaseClass
       Public Overrides Function ToString(ByVal _
          Format As String, ByVal Provider As IFormatProvider) _
          As String
           ToString = UCase(Value)
       End Function
       Public Sub New(ByVal Value As String)
            MyBase.New(Value)
        End Sub
   End Class
   Sub Main()
        Dim A As New BaseClass ("Hello! how are you all?")
        Dim B As New DerivedClass ("Welcome to VB.NET heaven")
       Console.WriteLine(A)
        Console.WriteLine(B)
        Console.WriteLine(A.CompareTo(B))
        Console.ReadLine()
   End Sub
End
Module

OUTPUT:

reimplmentInterface.gif

I hope now it is clear to you that how to Re-Implement interface in VB.NET.

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