Private Class TestData1
  Implements IComparable(Of TestData1)

  Public Property Stringa() As String
  Public Property Numero() As Integer
  Public Property Data() As DateTime

  Public Property Nome As String

  Public Function CompareTo(other As TestData1) As Integer Implements System.IComparable(Of TestData1).CompareTo
    If other Is Nothing Then Return 1

    Dim result As Integer = String.Compare(Me.Stringa, other.Stringa)

    If result <> 0 Then
      Return result
    Else
      result = Math.Sign(Me.Numero - other.Numero)
      If result <> 0 Then
        Return result
      Else
        Return DateTime.Compare(Me.Data, other.Data)
      End If
    End If

  End Function
End Class