function SendMail(const From, Dest, Subject, Text, FileName: PChar;
Outlook: boolean):Integer;
var
 Message: TMapiMessage;
 Recipient, Sender: TMapiRecipDesc;
 File_Attachment: TMapiFileDesc;

 function MakeMessage: TMapiMessage;
 begin
   FillChar(Sender, SizeOf(Sender), 0);
   Sender.ulRecipClass := MAPI_ORIG;
   Sender.lpszAddress := From;

   FillChar(Recipient, SizeOf(Recipient), 0);
   Recipient.ulRecipClass := MAPI_TO;
   Recipient.lpszAddress := Dest;

   FillChar(File_Attachment, SizeOf(File_Attachment), 0);
   File_Attachment.nPosition := Cardinal(-1);
   File_Attachment.lpszPathName := FileName;

   FillChar(Result, SizeOf(Result), 0);
   with Message do begin
     lpszSubject := Subject;
     lpszNoteText := Text;
     lpOriginator := @Sender;
     nRecipCount := 1;
     lpRecips := @Recipient;
     nFileCount := 1;
     lpFiles := @File_Attachment;
   end;
 end;

var
 SM: TFNMapiSendMail;
 MAPIModule: HModule;
 MAPI_FLAG: Cardinal;
begin
 if Outlook then
  MAPI_FLAG:=MAPI_DIALOG
 else
  MAPI_FLAG:=0;
 MAPIModule := LoadLibrary(PChar(MAPIDLL));
 if MAPIModule = 0 then
   Result := -1
 else
   try
     @SM := GetProcAddress(MAPIModule, 'MAPISendMail');
     if @SM <> nil then begin
       MakeMessage;
       Result := SM(0, Application.Handle, Message, MAPI_FLAG, 0);
     end else Result := 1;
   finally
     FreeLibrary(MAPIModule);
   end;
end;

  if OpenDialog1.Execute then
     begin
        TIdAttachmentFile.Create(IdMsgSend.MessageParts, OpenDialog1.FileName);
        ResetAttachmentListView;
     end;

IdMsgSend: TIdMessage;