private void OnViewUpdate(object sender, ExportStatusChangedArgs args)
        {
            IPageView view     = (IPageView)sender;
            TabPage   currTab  = tabControl.SelectedTab;
            IPageView currView = (IPageView)currTab.Controls[0];

            if (view.Equals(currView) && _readyForExport != args.IsReadyForExport)
            {
                _readyForExport = args.IsReadyForExport;
                if (OnExportStatusChanged != null)
                {
                    OnExportStatusChanged(this, args);
                }
            }
        }