打开Outlook发邮件界面，发邮件

        private void SendMailAttach(string to,string bcc,string subject,string body,bool html,string FileNameforEMail)
        {
            Outlook._Application oApp = new Outlook.Application();      

            Outlook.NameSpace oNameSpace= oApp.GetNamespace("MAPI");              

            try
            {
                oNameSpace.Logon(Missing.Value, Missing.Value,true,true);  

                Outlook.MAPIFolder oOutboxFolder = oNameSpace.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderSentMail);

                Outlook.ApplicationClass a = new Outlook.ApplicationClass();

                Outlook.MailItemClass tt;

                tt=(Outlook.MailItemClass)a.CreateItem(OlItemType.olMailItem);               

                tt.To=to;
                tt.CC = bcc;

                tt.Subject=subject;

                if(html)
                {
                    tt.HTMLBody=body;
                }
                else
                {
                    tt.Body=body;    
                }

                tt.SaveSentMessageFolder=oOutboxFolder;

                tt.Attachments.Add(FileNameforEMail,Missing.Value,Missing.Value,Missing.Value);

                tt.Display(null);                
            }
            finally
            {
                oNameSpace.Logoff();

            }

        }