VSTO PowerPoint 代码删除Shape后再恢复出现无法再次获取的问题

做PowerPoint的VSTO插件项目，遇到个很奇怪的问题，当代码执行删除某些Shape时，没问题，但是操作Undo也就是恢复后，无法再次获取到之前删除的对象，这种情况只在Office2007中出现，亲测2010没问题。

就在快要放弃的时候，终于看到了这个

传送门：https://www.add-in-express.com/creating-addins-blog/2014/06/24/exception-hresult-0x800a01a8/

关键内容搬运如下：

private void adxRibbonButton1_OnClick(object sender, IRibbonControl control, bool pressed) {
    PowerPoint.DocumentWindow activeWindow = PowerPointApp.ActiveWindow;
    if (activeWindow != null) {
        PowerPoint.View view = activeWindow.View;
        if (view != null) {
            object obj = view.Slide;
            if (obj != null) {
                if (obj is PowerPoint.Slide) {
                    PowerPoint.Shapes shapes = (obj as PowerPoint.Slide).Shapes;
                    if (shapes.HasTitle == Microsoft.Office.Core.MsoTriState.msoTrue) {
                        PowerPoint.Shape titleShape = shapes.Title;
                        object titleParent = null;
                        try {
                            titleParent = titleShape.Parent;
                        } catch (Exception ex) {
                            MessageBox.Show(ex.Message);
                        }
                        if (titleParent != null) {
                            // use titleParent
                        }
                        titleShape.Delete();
                        // leaving the COM object below unreleased causes 0x800A01A8 if you click Undo in the PP UI and invoke this code anew
                        Marshal.ReleaseComObject(titleShape); titleShape = null;
                    }
                    Marshal.ReleaseComObject(shapes); shapes = null;
                }
                Marshal.ReleaseComObject(obj); obj = null;
            }
            Marshal.ReleaseComObject(view); view = null;
        }
        Marshal.ReleaseComObject(activeWindow); activeWindow = null;
    }
}

理解后，很容易就解决了这个问题，分享一下