/// <summary>
        /// set the confidential level
        /// </summary>
        /// <param name="sensitive"> confidential level string</param>
        private void SetWorkbookSensitive(string sensitive)
        {
            try
            {
                Microsoft.Office.Core.DocumentProperties prp = Globals.ThisAddIn.Application.ActiveDocument.CustomDocumentProperties;

                bool isSenitive = false;

                foreach (Microsoft.Office.Core.DocumentProperty documentProperty in prp)
                {
                    if (documentProperty.Name.Equals("Sensitive"))
                    {
                        //MessageBox.Show(documentProperty.Value);
                        //InitRabbionControl(documentProperty.Value);
                        documentProperty.Value = sensitive;
                        isSenitive             = true;
                    }
                }

                if (isSenitive == false)
                {
                    prp.Add("Sensitive", false, Microsoft.Office.Core.MsoDocProperties.msoPropertyTypeString, sensitive, null);
                }

                Globals.ThisAddIn.InitRabbionControl(sensitive);
            }
            catch (Exception)
            {
                throw;
            }
        }
        void Application_DocumentBeforeSave(Word.Document Doc, ref bool SaveAsUI, ref bool Cancel)
        {
            Microsoft.Office.Interop.Word.Document   nativeDocument = Globals.ThisAddIn.Application.ActiveDocument;
            Microsoft.Office.Tools.Word.Document     vstoDocument   = Globals.Factory.GetVstoObject(nativeDocument);
            Microsoft.Office.Core.DocumentProperties properties     = (Office.DocumentProperties)vstoDocument.CustomDocumentProperties;
            string messageBoxText = "We noticed you haven't classified your document, would you like to opt out of classifying this document?";
            string caption        = "Classify Your Document";

            object oBasic = Application.WordBasic;

            object fIsAutoSave =
                oBasic.GetType().InvokeMember(
                    "IsAutosaveEvent",
                    BindingFlags.GetProperty,
                    null, oBasic, null);

            MessageBoxButtons button = MessageBoxButtons.YesNo;
            MessageBoxIcon    icon   = MessageBoxIcon.Warning;

            if (ReadDocumentProperty2("Classification") == null && !(int.Parse(fIsAutoSave.ToString()) == 1))
            {
                DialogResult result = MessageBox.Show(messageBoxText, caption, button, icon);
                switch (result)
                {
                case DialogResult.Yes:
                    properties.Add("Classification", false,
                                   Microsoft.Office.Core.MsoDocProperties.msoPropertyTypeString,
                                   "Not Classified");
                    break;

                case DialogResult.No:
                    MessageBox.Show("Please add a classification and try saving the document again", "Classify", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    Cancel = true;
                    break;
                }
            }
        }