程序如下：
定义API
FUNCTION ulong FindWindowA(ulong classname,string windowname) LIBRARY "user32.dll"
FUNCTION boolean DestroyWindow(ulong w_handle) LIBRARY "USER32.DLL"
cb_1的clicked事件如下：
string ls_winname
ulong l_handle
boolean rtn
ls_winname = '纸牌'
l_handle = FindWindowA(0,ls_winname)
rtn = DestroyWindow(l_handle)
messagebox('',string(rtn))
当运行游戏纸牌时，点击cb_1后不能关闭。rtn返回值为false，请高手指点，谢谢。