对象关闭时，不允许操作

ls_pwd:=EncryStrHex(edt_new .Text, 'SunYour');
  with dmfrm.con1 do
    begin
      BeginTrans;
      sqltext:='update  b_operator set log_pwd='''+ls_pwd+''' where log_name='''+app_Account+'''';
      try
        execute(sqltext);
        committrans;
        ShowMessage('密码修改成功！');
      except
        RollbackTrans ;
        showmessage('密码修改失败！');
      end;
      Close;
    end;