Next code contains nice function for sending Outlook calendar event by SMTP. Good for creating and distributing calendar events from your applications.
It is good sample how to use tmimemess for sending mails too.
uses Classes, SysUtils, synautil, smtpsend, mimemess, mimepart, synachar, jcldatetime; function SendMime(const SMTPHost, Username, Password: string; const Mime: TMimeMess): string; var SMTP: TSMTPSend; s, t: string; sendOK: boolean; begin Result := ''; sendOK := false; SMTP := TSMTPSend.Create; try // if you need SOCKS5 support, uncomment next lines: // SMTP.Sock.SocksIP := '127.0.0.1'; // SMTP.Sock.SocksPort := '1080'; // if you need support for upgrade session to TSL/SSL, uncomment next lines: // SMTP.AutoTLS := True; // if you need support for TSL/SSL tunnel, uncomment next lines: // SMTP.FullSSL := True; SMTP.TargetHost := Trim(SeparateLeft(SMTPHost, ':')); s := Trim(SeparateRight(SMTPHost, ':')); if (s '') and (s SMTPHost) then SMTP.TargetPort := s; SMTP.Username := Username; SMTP.Password := Password; if SMTP.Login then begin if SMTP.MailFrom(GetEmailAddr(Mime.Header.From), Length(Mime.Lines.Text)) then begin s := Mime.Header.ToList.Text; repeat t := GetEmailAddr(Trim(FetchEx(s, ',', '"'))); if t '' then sendOK := SMTP.MailTo(t); if not sendOK then Break; until s = ''; sendOK := SMTP.MailData(Mime.Lines); if (sendOK) then begin result := sendOKString; end else begin result := 'Send FAIL with error: "' + SMTP.ResultString + '"'; end; end; SMTP.Logout; end; finally SMTP.Free; end; end; function ConvertToUTCDateString(const date: TDateTime): string; begin DateTimeToString(result, 'yyyymmdd"T"hhnnss"Z"', DateTimeToLocalDateTime(date)); end; function SendMailCalendarEvent(const MailFrom, MailTo, Subject, SMTPHost, user, pass, Summary, Location, Description: string; const FromDate, ToDate : TDateTime): string; var mime: TMimemess; mimePart, mimeHtml: TMimepart; i: integer; t: TStringList; begin result := ''; mime := TMimemess.create; t := TStringList.Create(); t.Add('BEGIN:VCALENDAR'); t.Add('PRODID:HourMailer'); t.Add('VERSION:2.0'); t.Add('METHOD:REQUEST'); t.Add('BEGIN:VEVENT'); t.Add('ATTENDEE;ROLE=REQ-PARTICIPANT;RSVP=TRUE:MAILTO:' + MailTo); t.Add('ORGANIZER:MAILTO:' + MailFrom); t.Add('DTSTART:' + ConvertToUTCDateString(FromDate)); t.Add('DTEND:' + ConvertToUTCDateString(ToDate)); t.Add('TRANSP:OPAQUE'); t.Add('SEQUENCE:0'); t.Add('UID:' + ConvertToUTCDateString(Now) + '@HourMailer'); t.Add('DTSTAMP:' + ConvertToUTCDateString(Now)); t.Add('SUMMARY:' + CharsetConversion(Summary, GetCurCP, UTF_8)); if not(Location = '') then begin t.Add('LOCATION:' + CharsetConversion(Location, GetCurCP, UTF_8)); end; if not(description = '') then begin t.Add('DESCRIPTION:' + CharsetConversion(description, GetCurCP, UTF_8)); end; t.Add('PRIORITY:5'); t.Add('X-MICROSOFT-CDO-IMPORTANCE:1'); t.Add('CLASS:PUBLIC'); t.Add('BEGIN:VALARM'); t.Add('TRIGGER:-PT15M'); t.Add('ACTION:DISPLAY'); t.Add('DESCRIPTION:Reminder'); t.Add('END:VALARM'); t.Add('END:VEVENT'); t.Add('END:VCALENDAR'); try mimePart := mime.AddPart(nil); with mimePart do begin t.SaveToStream(DecodedLines); Primary := 'text'; Secondary := 'calendar; method=REQUEST'; CharsetCode := GetCurCP; EncodingCode := ME_8BIT; EncodePart; CharsetCode := UTF_8; EncodePartHeader; end; mime.header.from := MailFrom; mime.header.tolist.add(MailTo); mime.header.subject := Subject; mime.EncodeMessage; result := SendMime(SMTPHost, user, pass, mime); finally mime.free; t.Free; end; end;