ThisAddIn.cs

using System;
using Outlook = Microsoft.Office.Interop.Outlook;
using Microsoft.Office.Tools.Ribbon;
using System.Threading;

namespace NotifySecurity
{
    public partial class ThisAddIn
    {

        //Outlook.Inspectors inspectors;
        Outlook.Explorer currentExplorer = null;

        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {

            //new System.Threading.Thread(() =>
            //{
                CreateRibbonExtensibilityObject();
                #region declaration of the new event

                currentExplorer = this.Application.ActiveExplorer();
                if (currentExplorer == null) return;
                currentExplorer.SelectionChange += new Outlook.ExplorerEvents_10_SelectionChangeEventHandler
                    (CurrentExplorer_Event);
                #endregion



            //}).Start();


        }


        protected override Microsoft.Office.Core.IRibbonExtensibility CreateRibbonExtensibilityObject()
          {
              return new Ribbon1();
          }

        //        protected override Microsoft.Office.Core.IRibbonExtensibility CreateRibbonExtensibilityObject()



        #region action when a new mail is selected
        private void CurrentExplorer_Event()
        {


            //if (currentExplorer == null) return null


            Outlook.MAPIFolder selectedFolder =
                this.Application.ActiveExplorer().CurrentFolder;

            bool SelectedObjectIsMail = false;
            //String expMessage = "Your current folder is " + selectedFolder.Name + ".\n";
           // String itemMessage = "Item is unknown.";
            try
            {
                if (this.Application.ActiveExplorer().Selection.Count > 0)
                {
                    Object selObject = this.Application.ActiveExplorer().Selection[1];


                    if (selObject is Outlook.MailItem)
                    {
                        SelectedObjectIsMail = true;
                        /*
                         Outlook.MailItem mailItem =
                             (selObject as Outlook.MailItem);
                         itemMessage = "The item is an e-mail message." +
                             " The subject is " + mailItem.Subject + ".";
                         mailItem.Display(false);
                         */

                    }
                    else if (selObject is Outlook.ContactItem)
                    {
                        /*Outlook.ContactItem contactItem =
                            (selObject as Outlook.ContactItem);
                        itemMessage = "The item is a contact." +
                            " The full name is " + contactItem.Subject + ".";
                        contactItem.Display(false);
                        */
                    }
                    else if (selObject is Outlook.AppointmentItem)
                    {
                        /*
                        Outlook.AppointmentItem apptItem =
                            (selObject as Outlook.AppointmentItem);
                        itemMessage = "The item is an appointment." +
                            " The subject is " + apptItem.Subject + ".";
                            */
                    }
                    else if (selObject is Outlook.TaskItem)
                    {
                        /*
                        Outlook.TaskItem taskItem =
                            (selObject as Outlook.TaskItem);
                        itemMessage = "The item is a task. The body is "
                            + taskItem.Body + ".";
                            */
                    }
                    else if (selObject is Outlook.MeetingItem)
                    {
                        /*
                        Outlook.MeetingItem meetingItem =
                            (selObject as Outlook.MeetingItem);
                        itemMessage = "The item is a meeting item. " +
                             "The subject is " + meetingItem.Subject + ".";
                        */
                    }
                }
                // expMessage = expMessage + itemMessage;

                ThisRibbonCollection ribbonCollection =Globals.Ribbons[Globals.ThisAddIn.Application.ActiveInspector()];
                if (SelectedObjectIsMail)
                {
                    /* Ribbon1.
                     ribbonCollection.Ribbon1.comboBox1.Text = "Hello World";
                     */


                }
            }
            catch (Exception )
            {
               // expMessage = ex.Message;
            }
           // MessageBox.Show(expMessage);
        }
        #endregion

        #region action when a new mail is created
        void Inspectors_NewInspector(Microsoft.Office.Interop.Outlook.Inspector Inspector)
        {
            Outlook.MailItem mailItem = Inspector.CurrentItem as Outlook.MailItem;
            if (mailItem != null)
            {
                if (mailItem.EntryID == null)
                {
                    mailItem.Subject = "This text was added by using code";
                    mailItem.Body = "This text was added by using code";
                }

            }
        }
        #endregion

        #region DO NOT TOUCH
        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
            // Note: Outlook no longer raises this event. If you have code that
            //    must run when Outlook shuts down, see https://go.microsoft.com/fwlink/?LinkId=506785
        }

        #region VSTO generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisAddIn_Startup);
            this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);
        }

        #endregion

        #endregion

    }
}