[OutlookAddin] Issue with MailItem.SaveAs

[tuanpq]

Dear all,

I'm a newbie Outlook Add-in and I have developed a small Outlook Add-in, but now I have an issue with the Add-in. Sample source code is bellow:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using Outlook = Microsoft.Office.Interop.Outlook;
using Office = Microsoft.Office.Core;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.IO;

namespace OutlookAddIn1
{
    public partial class ThisAddIn
    {
        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            this.Application.ItemSend += new Microsoft.Office.Interop.Outlook.ApplicationEvents_11_ItemSendEventHandler(Application_ItemSend);
        }
        void Application_ItemSend(object Item, ref bool Cancel)
        {
            Outlook._MailItem mailItem = (Outlook._MailItem)Item;

            try
            {
                string strTempFileName = string.Empty;
                string strTempPath = Path.GetTempPath();
                DateTime dtCurrent = DateTime.Now;

                strTempFileName = string.Format("{0:0000}{1:00}{2:00}{3:00}{4:00}{5:00}{6:000}",
                                                dtCurrent.Year,
                                                dtCurrent.Month,
                                                dtCurrent.Day,
                                                dtCurrent.Hour,
                                                dtCurrent.Minute,
                                                dtCurrent.Second,
                                                dtCurrent.Millisecond);
                strTempFileName = strTempPath + strTempFileName + ".oft";
                mailItem.SaveAs(strTempFileName, Outlook.OlSaveAsType.olTemplate);
                File.Delete(strTempFileName);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                Marshal.ReleaseComObject(mailItem);
            }

            Cancel = true;
        }

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

        }

        #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
    }
}

Pre-condition:
1. There is at least one item in Draft folder.

Steps to procedure issue:
1. Start MS Outlook
2. Open an item in Draft folder
3. Click button [Send]
4. Close editor of current item. At this time, a message box is displayed [Do you want to save changes?] although I did not make any change.
5. Close MS Outlook. At this time, another message box is displayed [Do you want to save changes?] two times.

Question:
1. Why [Do you want to save changes?] message is displayed?
2. How can I disable the [Do you want to save changes?] message without calling MailItem.Save method?

(I'm using WinXP + MS Outlook 2010 + Visual Studio 2010 to develop the Add-in.)

Thanks for helping.