使用过滤器的Outlook项目查找不适用于已发送的项目

Question

我尝试使用find过滤邮件项目，它适用于收件箱项目，但在发送的项目中，它使用过滤器找不到项目。

    private void GetNewSyncSentMail()
    { 
        Outlook.MAPIFolder mailSentFolder = null;
        Outlook.Items mailItemsSent = null;
        Outlook.MailItem mailItemSent = null;
        try
        {
            mailSentFolder = Globals.objNS.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderSentMail);
            Debug.DebugMessage(3, "Get folder "+mailSentFolder.Name );
            mailItemsSent = mailSentFolder.Items;
            Debug.DebugMessage(3, "Get sent items " + mailItemsSent.Count);
            mailItemSent = mailItemsSent.Find(filter) as Outlook.MailItem;
            while (mailItemSent != null)
            {
                try
                {
                    //Do something
                }
                catch (Exception exInner)
                {
                    Debug.DebugMessage(2, "Error  GetNewSyncSentMail" + exInner.Message);
                }
                finally
                {
                    if (mailItemSent != null) Marshal.ReleaseComObject(mailItemSent);
                    mailItemSent = mailItemsSent.FindNext() as Outlook.MailItem;
                }
            }
        }
        catch (Exception ex)
        {
            Debug.DebugMessage(2, "Error in GetNewSyncWSinoSentMail" + ex.Message);
        }
        finally
        {
            if (mailItemsSent != null) Marshal.ReleaseComObject(mailItemsSent);
            if (mailSentFolder != null) Marshal.ReleaseComObject(mailSentFolder);
        }
    }

发送的项目满足outlook中的过滤器。但是在上面的代码中找不到。

这是过滤器

public static string syncW = (char)34 + "http://schemas.microsoft.com/mapi/string/{00020329-0000-0000-C000-000000000046}/syncW" + (char)34;
    public static string sID = (char)34 + "http://schemas.microsoft.com/mapi/string/{00020329-0000-0000-C000-000000000046}/sID" + (char)34;
    public string filter = "@SQL=((" + syncWi + " = 'True') AND ((" + sID + " = '') OR (" + sID + " IS NULL)))";