Public Class AttivitaCollection
        Inherits BindingList(Of Attivita)

        Protected _adapter As AdapterAttivita
        'Variabili per l'ordinamento
        Private _Direction As ListSortDirection = ListSortDirection.Ascending
        Private _SortProperty As PropertyDescriptor

        Sub New()
            Try
                _adapter = New AdapterAttivita()
            Catch ex As Exception
                Throw ex
            End Try
            Popola()
            Me.AllowNew = True
        End Sub

        Public Overloads Sub AddNew(ByVal sender As Object, ByVal e As System.ComponentModel.AddingNewEventArgs) Handles Me.AddingNew
            Me.Items.Add(New Attivita(CType(_adapter.AddAttivita(), IAttivitaDB)))
        End Sub

        Protected Overridable Sub Popola()
            For Each at As IAttivitaDB In _adapter.GetAttivita()
                Me.Items.Add(New Attivita(CType(at, IAttivitaDB)))
            Next
        End Sub

        Public Sub Update()
            _adapter.Update()
            Popola()
        End Sub

        'Indica che è una collection Ordinabile
        Protected Overrides ReadOnly Property SupportsSortingCore() As Boolean
            Get
                Return True
            End Get
        End Property

        Protected Overrides ReadOnly Property SortPropertyCore() As System.ComponentModel.PropertyDescriptor
            Get
                Return _SortProperty
            End Get
        End Property

        Protected Overrides ReadOnly Property SortDirectionCore() As System.ComponentModel.ListSortDirection
            Get
                Return _Direction
            End Get
        End Property

        Protected Overrides Sub ApplySortCore(ByVal prop As System.ComponentModel.PropertyDescriptor, ByVal direction As System.ComponentModel.ListSortDirection)
            Dim items As List(Of Attivita) = CType(Me.Items, List(Of Attivita))
            _Direction = direction
            _SortProperty = prop
            If (Not (items) Is Nothing) Then
                Select Case prop.DisplayName
                    Case "Inizio"
                        items.Sort(New Attivita.InizioComparer(direction))
                End Select
            End If
        End Sub

        Protected Overrides Sub RemoveSortCore()
            MyBase.RemoveSortCore()
        End Sub

       Protected Overrides Sub OnListChanged(ByVal e As System.ComponentModel.ListChangedEventArgs)
            MyBase.OnListChanged(e)
        End Sub
    End Class