Protected Sub CalDate1_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles CalDate1.SelectionChanged
        'ottengo il riferimento al textbox da modificare
        Dim MyTxt As TextBox = DirectCast(Me.FindControl("TxtData1"), TextBox)
        'se esiste lo riempio con la data selezionata
        If Not MyTxt Is Nothing Then
            MyTxt.Text = DirectCast(sender, Calendar).SelectedDate.ToShortDateString()
        End If
    End Sub