PostThreadMessages is impossible!because when the thread is busy ,thread hardly hang up and can not receive message.
I think you can not solution the problem perfectly,because at first it is your wrong!You said "工作线程中有几条语句十分费时",what is "十分费时"?If routines waste too much time ,it should support a functionality "time-out",and it should return "time-out" error !
if "十分费时" is not "time-out",you have to kill thread directly.
I am sorry that I can not input chinese in this computer.