/// <summary>
            /// Removes Comments, and Hidden Slides of PowerPoint file
            /// </summary> 
            public static void RemoveHiddenData()
            {
                try
                {
                    //ExStart:RemoveHiddenDataInPPT
                    // initialize PptFormat
                    PptFormat pptFormat = new PptFormat(Common.MapSourceFilePath(filePath));

                    // get hidden data
                    PptInspectionResult hiddenData = pptFormat.InspectDocument();

                    // get comments
                    PptComment[] comments = hiddenData.Comments;

                    if (comments.Length > 0)
                    {
                        // remove all comments
                        pptFormat.RemoveHiddenData(new PptInspectionOptions(PptInspectorOptionsEnum.Comments));
                        Console.WriteLine("Comments removed.");

                        // and commit changes
                        pptFormat.Save();
                        Console.WriteLine("Changes saved successfully!");
                    }
                    else
                    {
                        Console.WriteLine("No comments found!");
                    }
                    //ExEnd:RemoveHiddenDataInPPT

                }
                catch (Exception exp)
                {
                    Console.WriteLine(exp.Message);
                }
            }
            /// <summary>
            /// Gets Comments, and Hidden Slides of PowerPoint file
            /// </summary> 
            public static void GetHiddenData()
            {
                try
                {
                    //ExStart:GetHiddenDataInPPT
                    // initialize PptFormat
                    PptFormat pptFormat = new PptFormat(Common.MapSourceFilePath(filePath));

                    // get hidden data
                    PptInspectionResult hiddenData = pptFormat.InspectDocument();

                    // get comments
                    PptComment[] comments = hiddenData.Comments;

                    // get slides
                    PptSlide[] slides = hiddenData.HiddenSlides;

                    foreach (PptComment comment in comments)
                    {
                        Console.WriteLine("Author: {0}, Slide: {1}", comment.Author, comment.SlideId);
                    }
                    //ExEnd:GetHiddenDataInPPT
                }
                catch (Exception exp)
                {
                    Console.WriteLine(exp.Message);
                }
            }