我是编写了一个DLL的弹窗，然后MFC应用程序去调用就出现了这个问题：
关于这个问题主要问题点在 ASSERT(pMap != NULL); ASSERT((CWnd*)p == this); // must be us
这两个问题在release版本的时候并不展现，但并不代表没有问题：
出问题的源码如下：
#ifdef _DEBUGvoid CWnd::AssertValid() const{if (m_hWnd == NULL)return; // null (unattached) windows are valid// check for special wnd??? valuesASSERT(HWND_TOP == NULL); // same as desktopif (m_hWnd == HWND_BOTTOM)ASSERT(this == &CWnd::wndBottom);else if (m_hWnd == HWND_TOPMOST)ASSERT(this == &CWnd::wndTopMost);else if (m_hWnd == HWND_NOTOPMOST)ASSERT(this == &CWnd::wndNoTopMost);else{// should be a normal windowASSERT(::IsWindow(m_hWnd));// should also be in the permanent or temporary handle mapCHandleMap* pMap = afxMapHWND();ASSERT(pMap != NULL);CObject* p=NULL;if(pMap){ASSERT( (p = pMap->LookupPermanent(m_hWnd)) != NULL ||(p = pMap->LookupTemporary(m_hWnd)) != NULL);}ASSERT((CWnd*)p == this); // must be us// Note: if either of the above asserts fire and you are// writing a multithreaded application, it is likely that// you have passed a C++ object from one thread to another// and have used that object in a way that was not intended.// (only simple inline wrapper functions should be used)//// In general, CWnd objects should be passed by HWND from// one thread to another. The receiving thread can wrap// the HWND with a CWnd object by using CWnd::FromHandle.//// It is dangerous to pass C++ objects from one thread to// another, unless the objects are designed to be used in// such a manner.}}#endif
网上的资料大都说是多线程引起的，其实我没有多线程，只是有子窗口；只是MFC本身消息机制问题导致的，我的部分代码是这样写的：
代码里都是这种风格的，然后百思不得其解，仍然没有解决问题，实在没有办法了；最后对于窗口DLL又重新封装了一遍，类似这样：
重新编写之后就可以了！