RegisterClassEx（）函数注册失败返回0

_Elegant 2014-04-19 08:36:12

vs2012生成一个mfc程序实现窗口类创建，注册，显示及更新。

BOOL CMyOwnerDrawApp::InitInstance()

{

	CWinApp::InitInstance();

	CMainFrame* pMainFrame = new CMainFrame();

	pMainFrame->CreateEx(0,

			_T("MAINFRAME"),

			_T("自绘程序"),

			WS_POPUPWINDOW | WS_MAXIMIZEBOX | WS_MINIMIZEBOX | WS_THICKFRAME,

			CW_USEDEFAULT, CW_USEDEFAULT,

			CW_USEDEFAULT, CW_USEDEFAULT,

			NULL, NULL);

	m_pMainWnd = pMainFrame;

	pMainFrame->ShowWindow(SW_SHOW);

	pMainFrame->UpdateWindow();

	return TRUE;

}

BOOL CMainFrame::PreCreateWindow(CREATESTRUCT& cs)

{

	HINSTANCE hInstance = (HINSTANCE)AfxGetInstanceHandle();

	ASSERT(hInstance);



	WNDCLASSEX wcex;

	wcex.cbSize = sizeof(WNDCLASSEX);

	BOOL bRet = GetClassInfoEx( hInstance, cs.lpszClass, &wcex);

	if (bRet)

	{

		return TRUE;

	}



	wcex.style = CS_VREDRAW | CS_HREDRAW | CS_DBLCLKS;

	wcex.lpfnWndProc = AfxWndProc;

	wcex.cbSize = 0;

	wcex.cbWndExtra = 0;

	wcex.hInstance = hInstance;

	wcex.hIcon = (HICON)::LoadIcon(hInstance, MAKEINTRESOURCE(IDR_MAINFRAME));

	wcex.hIconSm = (HICON)::LoadIcon(hInstance, MAKEINTRESOURCE(IDR_MAINFRAME));

	wcex.hCursor = ::LoadCursor(NULL, IDC_ARROW);

	wcex.hbrBackground = (HBRUSH)::GetStockObject(WHITE_BRUSH);

	wcex.lpszMenuName = NULL;

	wcex.lpszClassName = cs.lpszClass;

	bRet = RegisterClassEx(&wcex);

	return bRet;

}

如此这样，可是在调用bRet = RegisterClassEx(&wcex);返回值却是0，意思就是没注册成功咯？
我按着别人视频一步步来的，重新看了好几遍，就是找不到什么原因。
我调试了一下程序在pMainFrame->ShowWindow(SW_SHOW);时崩溃了。
求大神帮忙看看问题出在哪里。感谢！！

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