MFC主线程使用WaitForSingleObject阻塞的问题

在MFC程序的主线程中如果使用WaitForSingleObject等线子线程，而子线程里使用了有关于消息的函数，比如SetWindowText,InsertItem,SetItemText这些函数，就有会导致主主线程阻塞问题，看看这段代码。

DWORD WINAPI ThreadProc(
LPVOID lpParameter   // thread data
)
{
CMFCWaitThreadDlg *pDlg = (CMFCWaitThreadDlg*)lpParameter;

for (int i=0;i<=10;i++)
{
OutputDebugStringA("test");
Sleep(2000);
pDlg->SetWindowText(_T("HEHE"));

}
return true;
}
void CMFCWaitThreadDlg::OnBnClickedOk()
{
// TODO: 在此添加控件通知处理程序代码
DWORD dwID;
HANDLE hThread;
hThread = CreateThread(0,0,ThreadProc,this,0,&dwID);

DWORD dwRet = WaitForSingleObject(hThread,INFINITE);
if (dwRet == WAIT_OBJECT_0)
{
MessageBoxA(0,"Thread exit",0,0);
}

}

主线程出现阻塞问题的原因是，因为SetWindowText调用了SendMessage,借助了消息循环，然后主线程又Waitxxxxx，必然会阻塞，最终导致工作线程Crash掉了。还好微软提供了另一个函数MsgWaitForMultipleObjects，用这个就能搞定了，看看下面这段代码，把WaitForSingleObject那一段给替换了，跑一跑试试，就没问题了。

DWORD WINAPI ThreadProc(
LPVOID lpParameter   // thread data
)
{
CMFCWaitThreadDlg *pDlg = (CMFCWaitThreadDlg*)lpParameter;

for (int i=0;i<=10;i++)
{
OutputDebugStringA("test");
Sleep(2000);
pDlg->SetWindowText(_T("HEHE"));

}
return true;
}
void CMFCWaitThreadDlg::OnBnClickedOk()
{
// TODO: 在此添加控件通知处理程序代码
DWORD dwID;
HANDLE hThread;
hThread = CreateThread(0,0,ThreadProc,this,0,&dwID);

while(TRUE)
{

DWORD result ; 
MSG msg ; 

result = MsgWaitForMultipleObjects(1, &hThread, 
FALSE, INFINITE, QS_ALLINPUT); 

if (result == (WAIT_OBJECT_0))
{
break;
} 
else 
{ 
PeekMessage(&msg, NULL, 0, 0, PM_REMOVE);
DispatchMessage(&msg); 
} 
}

MessageBoxA(0,"Thread exit",0,0);

}