//通过会话ID得到会话名称

procedure GetSessionUserName(dwSessionId: dword; var UserName: string);

var

  bRes: boolean;

  dwBufferLen: dword;

  Ptr: LPTSTR;

begin

  bRes := WTSQuerySessionInformation(WTS_CURRENT_SERVER_HANDLE, dwSessionId, WTSUserName, Ptr, dwBufferLen);

  if bRes = false then

  begin

       UserName := '';

        exit;

  end;

  UserName := PWideChar(Ptr);

end;

GetSessionUserName(SessionId,UserName);

 showmessage(UserName);