请问我这段多线程代码为什么会死机？
我在写个多线程的代码，建立一个对话框，放置“开始”“通知”“进度条”控件。我的目的是按“开始”执行“ThreadFunc”函数，按“停止”中止执行。代码如下：
void CSolverDlg::ForceQuit(){ SetEvent(hExit);};BOOL CSolverDlg::IsForceQuit(){ return WaitForSingleObject(hExit,0) == WAIT_OBJECT_0 ;};void CSolverDlg::OnBnClickedStart(){ // TODO: 在此添加控件通知处理程序代码 if (m_MyThread != NULL) { DWORD dwExitCode = -1; VERIFY( GetExitCodeThread(*m_MyThread, &dwExitCode) ); if (dwExitCode == STILL_ACTIVE) { TRACE("是否在运行1\n"); return; } delete m_MyThread; m_MyThread = NULL; } m_MyThread =AfxBeginThread( ThreadFunc, (LPVOID)this, THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED, NULL); ASSERT(m_MyThread); m_MyThread->m_bAutoDelete = FALSE; m_MyThread->ResumeThread();}void CSolverDlg::OnBnClickedStop(){ // TODO: 在此添加控件通知处理程序代码 if (m_MyThread != NULL) { DWORD dwExitCode = -1; VERIFY( GetExitCodeThread(*m_MyThread, &dwExitCode) ); if (dwExitCode == STILL_ACTIVE) { ForceQuit(); WaitForSingleObject(*m_MyThread,INFINITE); delete m_MyThread; m_MyThread = NULL; } } else TRACE("已结束\n");}UINT ThreadFunc(LPVOID pParam){ CSolverDlg * pMain = (CSolverDlg *) pParam; //强制转换获得传入的类对象指针 pMain->m_Progress.SetRange(0, 30 ); for (int i=0; i<30; i++) { TRACE("在运行11\n") ; if (pMain->IsForceQuit()) { TRACE("停止1\n") ; return -1; } TRACE("在运行13\n") ; Sleep(5000);//休眠5秒钟 TRACE("在运行14\n") ; pMain->m_Progress.SetPos(i); TRACE("在运行12\n") ; } return 0;};