Converting C# fluent interface to code in VB.NET

Question

I have the following C# code which I'm trying to convert to VB.NET. I also want to replace the "Console.WriteLine"s with callbacks.

I think and hope I've managed to convert it to some extent:

nInteractorsAgent
    .AddInteractorFor(currentWindowBounds, Literals.RootId, 0, currentWindowHandle.ToString(), "MyFirstActivatable")
    .WithActivatable()
    .HasActivationFocus(id => Console.WriteLine("Id: {0} got activation focus.", id))
    .SetTentativeFocusEnabled(true)
    .HasTentativeFocus(id => Console.WriteLine("Id: {0} got tentative activation focus.", id))
    .WhenFocusChanged((id, hasTentativeFocus, hasActivationFocus) => { })
    .LostFocus(id => Console.WriteLine("Id: {0} lost focus.", id))
    .WhenActivated(id => Console.WriteLine("Id: {0} activated", id));

My approach in VB.NET is this:

Dim v1 As VirtualInteractor = nInteractorsAgent.AddInteractorFor(currentWindowBounds, Literals.RootId, 0, "0", "MyFirstActivatable").WithActivatable().HasActivationFocus(Sub() HasActivationFocus(v1.Id)).SetTentativeFocusEnabled(True).HasTentativeFocus(Sub() HasTentativeFocus(v1.Id)).WhenFocusChanged(Sub() WhenFocusChanged(v1.Id, False, False)).LostFocus(Sub() LostFocus(v1.Id)).WhenActivated(Sub() WhenActivated(v1.Id))

Public Shared Sub HasActivationFocus(ByVal id As String)

End Sub
Public Shared Sub HasTentativeFocus(ByVal id As String)

End Sub
Public Shared Sub WhenFocusChanged(ByVal id As String, ByVal hasTentativeFocus As Boolean, ByVal hasActivationFocus As Boolean)

End Sub
Public Shared Sub WhenFocusChanged()

End Sub
Public Shared Sub LostFocus(ByVal id As String)

End Sub
Public Shared Sub WhenActivated(ByVal id As String)

End Sub

However, the compiler tells me that something is wrong about

.WhenFocusChanged(Sub() WhenFocusChanged(v1.Id, False, False))

and

.WhenActivated(Sub() WhenActivated(v1.Id))

The compiler tells me that there's no version of WhenFocusChanged. The declarations are these:

    <Extension>
    Public Shared Function WhenFocusChanged(behaviors As IEnumerable(Of ActivatableBehavior), action As ActivationFocusChangedCallback) As IEnumerable(Of ActivatableBehavior)
    <Extension>
    Public Shared Function WhenFocusChanged(behavior As ActivatableBehavior, action As ActivationFocusChangedCallback) As ActivatableBehavior

Can anybody show me what I'm doing wrong here and how to do it correctly? I don't know which information apart from the given is important for readers in this case.

Thank you.

Answer 1

That won't work like the original code. You need a mix of lambda and delegate . Here's a quick example of something similar in vb.net.

Module Module1

    Sub Main()

        Dim o As New Test

        o.DoSomething(Sub(paramName) Console.WriteLine("The id is {0}", paramName))

    End Sub

End Module

Class Test

    Public Property ID As Integer = 10

    Delegate Sub SomeDelegate(ByVal id As Integer)

    Public Function DoSomething(ByVal f As SomeDelegate) As Test

        f(Me.ID)

        Return Me
    End Function

End Class