Binding in code from textbox to collection

Question

Hi everybody  :D

I try to bind a textbox to a collection, so if the value of the item in the collection changes the textbox.text changes… but I cannot get it to work.

When I set the binding it gets the correct value, but if the collection changes the value don’t. I don’t know how to update it. I tried the examples in the help, but they don’t work for me.

    Public Class Valor
        Implements INotifyPropertyChanged

        ' Events
        Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

        ' Methods
        Public Sub New(ByVal vvv As Integer)
            Me._vvv = vvv
        End Sub

        ' Properties
        Public Property vvv() As Integer
            Get
                Return Me._vvv
            End Get
            Set(ByVal value As Integer)
                Me._vvv = value
                Me.OnPropertyChanged()
            End Set
        End Property

        Private Sub OnPropertyChanged()
            RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("vvv"))
        End Sub

        ' Fields
        Private _vvv As String
    End Class


    Public MyCantidades As New ObservableCollection(Of Valor)

                'Cantidad
                Dim Cantidad1 = New TextBlock
                Cantidad1.FontSize = 30
                Dim Enlace As Binding = New Binding()
                Enlace.Source = MyCantidades.Item(3).vvv
                Enlace.Mode = 1
                Cantidad1.SetBinding(TextBlock.TextProperty, Enlace)

                ListaVarios.Children.Add(Cantidad1)

and one boton to change the collection

    Private Sub MasClick(sender As Object, e As RoutedEventArgs)

        MyCantidades.Item(3).vvv = MyCantidades.Item(3).vvv + 1

    End Sub

Ok, when I press the button the collection changes, but the textblock doesnt update.

¿Any clues?

Thank you in advance :D