[VB.NET] Scrittura / Lettura su file binary

[S0nic]

ho qualche problema

non mi risulta.....

non so dove sbaglio

ho fatto così

  Function RemoveIndex(ByVal programma As String, ByVal lista As ArrayList) As PWD
        Dim mystruc As PWD
        For i As Integer = 0 To lista.Count - 1
            mystruc = CType(lista(i), PWD)
            If mystruc.Programma = programma Then
                lista.RemoveAt(i)
                Exit For
            End If
        Next
    End Function

    Sub Remove()
        Dim lista As ArrayList
        Dim stream As FileStream = File.Open(Application.StartupPath & "\prova.bin", FileMode.Open)
        Dim formatter As New BinaryFormatter()
        lista = formatter.Deserialize(stream)
        Dim mystruc As PWD = RemoveIndex(ComboBox1.Text, lista)

        'TextBox1.Text = mystruc.Programma
        'TextBox2.Text = mystruc.Username
        'TextBox3.Text = mystruc.Password
        'TextBox4.Text = mystruc.Note

        stream.Close()
    End Sub

per la modifica invece:

 Sub ChangeIndex(ByVal programma As String, ByVal lista As ArrayList, ByVal password As String, ByVal userName As String, Optional ByVal note As String = "")
        Dim mystruc As PWD
        For i As Integer = 0 To lista.Count - 1
            mystruc = CType(lista(i), PWD)
            If mystruc.Programma = programma Then
                lista.RemoveAt(i)
                Dim myPWD As New PWD(programma, userName, password, note)
                myList.Add(myPWD)
                Exit For
            End If
        Next
    End Sub
    Sub Change()

        Dim lista As ArrayList
        Dim stream As FileStream = File.Open(Application.StartupPath & "\prova.bin", FileMode.Open)
        Dim formatter As New BinaryFormatter()
        lista = formatter.Deserialize(stream)
        Dim mystruc As PWD = ChangeIndex(TextBox1.Text, lista, TextBox3.Text, TextBox2.Text)


        stream.Close()
    End Sub

in quest'ultima parte il debug su questa riga

Dim mystruc As PWD = ChangeIndex(TextBox1.Text, lista, TextBox3.Text, TextBox2.Text)

mi dice che non produce nessun valore.


non riesco a far funzionare la rimozione e la modifica