GmailNotifier.MainForm.PrevButtonClicked C# (CSharp) Метод

        void PrevButtonClicked(object sender, ThumbnailButtonClickedEventArgs e)
        {
            if (_currentlyViewing == 0)
                return;

            _thumbForm.Invoke(new Action<int>(_thumbForm.UpdatePreviewThumb), _currentlyViewing - 1);

            EnableAppropriateButtons();
        }