If an interface defines a ReadOnly Property, how can an implementer provide the Setter to this property?

Question

Is there a way for implementers of an interface where a ReadOnly property is defined to make it a complete Read/Write Property ?

Answer 1

In Visual Basic, when you implement a method or property from an interface, you can change its name and its visibility. You can leverage that capability to handle the case you are asking about. Prior to Visual Studio 2015, I often did this:

Interface:

Public Interface SomeInterface
    ReadOnly Property SomeProperty As String
End Interface

Implementing Class:

Public Class SomeClass
    Implements SomeInterface

    Public Property SomeProperty As String
    Private ReadOnly Property SomeProperty_ReadOnly As String Implements SomeInterface.SomeProperty
        Get
            Return Me.SomeProperty
        End Get
    End Property
End Class

The result is that SomeProperty is read-only when accessed through SomeInterface, but read-write when accessed through SomeClass:

Dim c As New SomeClass
c.SomeProperty = "hello" 'Write via class OK
Dim s1 = c.SomeProperty 'Read via class OK

Dim i As SomeInterface = c
Dim s2 = i.SomeProperty 'Read via interface OK
i.SomeProperty = "greetings" 'Syntax Error, interface property is read-only