Dim c_counter as Integer = 0
Private Sub FindIndex(ByVal sender As Object, ByVal args As RoutedEventArgs)
    Try
        Dim newText As TextBlock = New TextBlock()
        c_counter = c_counter + 1
        ' Add this element to the UIElementCollection of the DockPanel element.
        MainDisplayPanel.Children.Add(newText)
        ' Add a text node under the Text element. This text is displayed. 
        newText.Text = "New element #" & CStr(c_counter)
        DockPanel.SetDock(newText, Dock.Top)
        ' Display the Index number of the new element.    
        TxtDisplay.Text = "The Index of the new element is " & MainDisplayPanel.Children.IndexOf(newText)
    Catch ex As System.Exception
        System.Windows.MessageBox.Show(ex.Message)
    End Try
End Sub