Anonymous methods - C# to VB.NET

Question

I have a requirement to implement a single VB.NET instance of an application on a terminal server. To do this I am using code from the Flawless Code blog. It works well, except in the code is written in C# and uses an anonymous method which is not supported in VB.NET. I need to rewrite the following so that I can use it as an event in VB.NET.

static Form1 form;

static void singleInstance_ArgumentsReceived(object sender, ArgumentsReceivedEventArgs e)
    {
        if (form == null)
            return;

        Action<String[]> updateForm = arguments =>
            {
                form.WindowState = FormWindowState.Normal;
                form.OpenFiles(arguments);
            };
        form.Invoke(updateForm, (Object)e.Args); //Execute our delegate on the forms thread!
    }
}

Answer 1

You can use this code:

Private Shared form As Form1

Private Shared Sub singleInstance_ArgumentsReceived(ByVal sender As Object, ByVal e As ArgumentsReceivedEventArgs)
    If form Is Nothing Then Return
    form.Invoke(New Action(Of String())(AddressOf updateFormMethod), e.Args)
End Sub

Private Shared Sub updateFormMethod(ByVal arguments As String())
    form.WindowState = FormWindowState.Normal
    form.OpenFiles(arguments)
End Sub

Answer 2

In VB.NET in VS 2010 you can do the following:

Shared form As Form1
Shared Sub singleInstance_ArgumentsReceived(ByVal sender As Object, ByVal e As ArgumentsReceivedEventArgs)
    If form Is Nothing Then Return

    Dim updateForm As Action(Of String()) = Sub(arguments)
                                                form.WindowState = FormWindowState.Normal
                                                form.OpenFiles(arguments)
                                            End Sub

    form.Invoke(updateForm, e.args)

End Sub

Answer 3

This:

public void Somemethod()
{
    Action<String[]> updateForm = arguments =>
        {
            form.WindowState = FormWindowState.Normal;
            form.OpenFiles(arguments);
        };
}

Would be the same as:

public void Somemethod()
{
    Action<String[]> updateForm = OnAction;
}

//named method
private void OnAction(string[] arguments)
{
    form.WindowState = FormWindowState.Normal;
    form.OpenFiles(arguments);
}

Then you do the VB.net transition easily, to something like this:

Public Sub SomeMethod()

    Dim updateForm As Action(Of String()) = New Action(Of String())(AddressOf Me.OnAction)
    Me.form.Invoke(updateForm, New Object() { e })

End Sub

Private Sub OnAction(ByVal arguments As String())
    form.WindowState = FormWindowState.Normal
    form.OpenFiles(arguments)
End Sub