为什么CWnd :: CreateEx无法创建我的窗口? [英] Why is CWnd::CreateEx failing to create my window?

问题描述

我正在处理我们的32位MFC VC2010应用程序中发生的零星生产问题.该应用程序在Windows Server 2008 R2 Standard SP1 64位上运行.

I'm working on a sporadic production issue that's occurring within our 32 bit MFC VC2010 application. The application is running on Windows Server 2008 R2 Standard SP1 64-bit.

此问题是由于无法创建CWnd派生类而引起的.发生故障时，AfxUnhookWindowCreate方法在CWnd :: CreateEx中返回false.这是因为pThreadState-> m_pWndInit变量不为NULL.当HCBT_CREATEWND被钩住时，_AfxCbtFilterHook看起来应该将其设置为NULL，但似乎没有发生.我已经注销了CREATESTRUCT，并将其与发生故障与未发生故障以及参数基本相同的时间进行比较.

The issue is caused by a failure to create a CWnd derived class. When the failure occurs the AfxUnhookWindowCreate method returns false within CWnd::CreateEx. This is because the pThreadState->m_pWndInit variable is not NULL. It looks like _AfxCbtFilterHook should be setting this to NULL when HCBT_CREATEWND is hooked, but it appears this is not occurring. I've logged out the CREATESTRUCT and compared it to when the failure occurs vs. doesn't occur and the parameters are essentially the same.

有人对导致此问题的原因或如何确定原因有想法吗?谢谢！

Does anyone have ideas on what could cause this or how I could identify the cause? Thanks!

BOOL CWnd::CreateEx(DWORD dwExStyle, LPCTSTR lpszClassName,
LPCTSTR lpszWindowName, DWORD dwStyle,
int x, int y, int nWidth, int nHeight,
HWND hWndParent, HMENU nIDorHMenu, LPVOID lpParam)
{
...
if (!PreCreateWindow(cs))
{
    PostNcDestroy();
    return FALSE;
}

AfxHookWindowCreate(this);
HWND hWnd = ::AfxCtxCreateWindowEx(cs.dwExStyle, cs.lpszClass,
        cs.lpszName, cs.style, cs.x, cs.y, cs.cx, cs.cy,
        cs.hwndParent, cs.hMenu, cs.hInstance, cs.lpCreateParams);
...
if (!AfxUnhookWindowCreate())
    PostNcDestroy();        // cleanup if CreateWindowEx fails too soon
...

BOOL AFXAPI AfxUnhookWindowCreate()
{
_AFX_THREAD_STATE* pThreadState = _afxThreadState.GetData();
  #ifndef _AFXDLL
if (afxContextIsDLL && pThreadState->m_hHookOldCbtFilter != NULL)
{
    ::UnhookWindowsHookEx(pThreadState->m_hHookOldCbtFilter);
    pThreadState->m_hHookOldCbtFilter = NULL;
}
  #endif
if (pThreadState->m_pWndInit != NULL)
{
    pThreadState->m_pWndInit = NULL;
    return FALSE;   // was not successfully hooked
}
return TRUE;
}

LRESULT CALLBACK
_AfxCbtFilterHook(int code, WPARAM wParam, LPARAM lParam)
{
_AFX_THREAD_STATE* pThreadState = _afxThreadState.GetData();
if (code != HCBT_CREATEWND)
{
    // wait for HCBT_CREATEWND just pass others on...
    return CallNextHookEx(pThreadState->m_hHookOldCbtFilter, code,
        wParam, lParam);
}

 ...
        pThreadState->m_pWndInit = NULL;

推荐答案

我将问题归结为当前不应该执行的窗口过程挂钩.

I tracked the problem down to a window procedure hook that shouldn't have been executing at this time.

这篇关于为什么CWnd :: CreateEx无法创建我的窗口?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！