void SpreadsheetComponentControl_Loaded(object sender, RoutedEventArgs e)
        {
            DesignerItem parent = this.Parent as DesignerItem;

            data.BindPositionToCanvas(parent);
            data.PropertyChanged += data_PropertyChanged;

            // add Export Excel context menu to DesignerItem
            List <MenuItem> menuItems  = new List <MenuItem>();
            MenuItem        exportItem = new MenuItem()
            {
                Header  = "Export to Excel",
                Command = Command.ExportExcel
            };

            menuItems.Add(exportItem);
            parent.AddContextMenuItems(menuItems);

            grid.UpdateLayout();
            for (int row = 0; row < this.grid.Items.Count; ++row)
            {
                UpdateRow(row);
            }

            UpdateDisplay();
        }