Encrypting a dataset using AES, including compression

''' <summary>
''' This window handles all the data input for the dataset
''' </summary>
Class MainWindow
   Private Sub btnCreate_Click(sender As System.Object, e As System.Windows.RoutedEventArgs)
      Me.OpenTheDataSet(True)
   End Sub

   Private Sub btnOpen_Click(sender As System.Object, e As System.Windows.RoutedEventArgs)
      Me.OpenTheDataSet(False)
   End Sub

   Private Sub btnSave_Click(sender As System.Object, e As System.Windows.RoutedEventArgs)
      EncryptDataSetVB.DataHandler.SaveChanges()
   End Sub

   Private Sub btnCancel_Click(sender As System.Object, e As System.Windows.RoutedEventArgs)
      EncryptDataSetVB.DataHandler.CancelChanges()
   End Sub

   Private Sub Window_Closing(sender As Object, e As System.ComponentModel.CancelEventArgs)
      e.Cancel = Not Me.CheckPendingChanges()
   End Sub

   ''' <summary>
   ''' Checks if there are pending changes and if they shall be ignored.
   ''' </summary>
   ''' <returns>True if changes are ignored or there are none</returns>
   Private Function CheckPendingChanges() As Boolean
      Dim result As System.Windows.MessageBoxResult = MessageBoxResult.Yes

      If Not EncryptDataSetVB.DataHandler.TheDataSet Is Nothing Then
         If EncryptDataSetVB.DataHandler.TheDataSet.HasChanges() Then
            result = System.Windows.MessageBox.Show(
               "All the unsaved changes will be lost. Do you want to continue?",
               EncryptDataSetVB.DataHandler.AppTitle,
               MessageBoxButton.YesNo,
               MessageBoxImage.Question,
               MessageBoxResult.No)
         End If
      End If

      Return result = MessageBoxResult.Yes
   End Function

   ''' <summary>
   ''' Opens or creates the dataset
   ''' </summary>
   ''' <param name="create">Create a new dataset</param>
   ''' <returns>True if successful</returns>
   Private Function OpenTheDataSet(create As Boolean) As Boolean
      Dim authentication As Authentication

      ' Check if there are pending changes
      If (Not Me.CheckPendingChanges()) Then
         Return False
      End If

      ' Get authentication information
      authentication = New Authentication()
      authentication.Owner = Me
      authentication.CreateDataset = create
      authentication.UseCompression = Me.chkCompress.IsChecked
      If Not authentication.ShowDialog() Then
         Return False
      End If

      If (create) Then
         ' Create the dataset
         If (Not EncryptDataSetVB.DataHandler.CreateDataSet( _
            authentication.FileName, _
            authentication.UserName, _
            authentication.Password, _
            Me.chkCompress.IsChecked)) Then
            Return False
         End If
      Else
         ' Open the existing dataset
         If (Not EncryptDataSetVB.DataHandler.OpenDataSet( _
            authentication.FileName, _
            authentication.UserName, _
            authentication.Password, _
            Me.chkCompress.IsChecked)) Then
            Return False
         End If
      End If

      ' Show the data
      Me.gbData.Header = String.Format("Current dataset: {0}", EncryptDataSetVB.DataHandler.FileName)
      Me.dgContacts.ItemsSource = EncryptDataSetVB.DataHandler.TheDataSet.Contacts
      Me.btnSave.IsEnabled = True
      Me.btnCancel.IsEnabled = True

      Return True
   End Function

   Private Sub Button_Click(sender As System.Object, e As System.Windows.RoutedEventArgs)

   End Sub
End Class