作者：沧桑不尽，请尊重原创，转载注明。

MFC中封装很多常用的控件，把类名也给封装了，没有提供明显的接口出来，用win api写窗口程序，第一步就是注册窗口类

BOOL CWnd::CreateEx(DWORD dwExStyle, LPCTSTR lpszClassName,
LPCTSTR lpszWindowName, DWORD dwStyle,
const RECT& rect, CWnd* pParentWnd, UINT nID,
LPVOID lpParam /* = NULL */)
{
return CreateEx(dwExStyle, lpszClassName, lpszWindowName, dwStyle,
rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top,
pParentWnd->GetSafeHwnd(), (HMENU)(UINT_PTR)nID, lpParam);
}

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)
{
ASSERT(lpszClassName == NULL || AfxIsValidString(lpszClassName) ||
AfxIsValidAtom(lpszClassName));
ENSURE_ARG(lpszWindowName == NULL || AfxIsValidString(lpszWindowName));

// allow modification of several common create parameters
CREATESTRUCT cs;
cs.dwExStyle = dwExStyle;
cs.lpszClass = lpszClassName;
cs.lpszName = lpszWindowName;
cs.style = dwStyle;
cs.x = x;
cs.y = y;
cs.cx = nWidth;
cs.cy = nHeight;
cs.hwndParent = hWndParent;
cs.hMenu = nIDorHMenu;
cs.hInstance = AfxGetInstanceHandle();
cs.lpCreateParams = 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);

#ifdef _DEBUG
if (hWnd == NULL)
{
TRACE(traceAppMsg, 0, "Warning: Window creation failed: GetLastError returns 0x%8.8X/n",
GetLastError());
}
#endif

if (!AfxUnhookWindowCreate())
PostNcDestroy(); // cleanup if CreateWindowEx fails too soon

if (hWnd == NULL)
return FALSE;
ASSERT(hWnd == m_hWnd); // should have been set in send msg hook
return TRUE;
}

// TODO: 在此添加专用代码和/或调用基类
//VERIFY(AfxDeferRegisterClass(AFX_WND_REG));
//AfxEndDeferRegisterClass(AFX_WND_REG);
//cs.lpszClass = AfxRegisterWndClass(NULL);
WNDCLASS wndcls;

memset(&wndcls, 0, sizeof(WNDCLASS)); // start with NULL
// defaults

wndcls.style = CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;

//you can specify your own window procedure
wndcls.lpfnWndProc = ::DefWindowProc;
wndcls.hInstance = AfxGetInstanceHandle();
wndcls.hIcon = NULL; // or load a different icon
wndcls.hCursor =NULL;
wndcls.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);
wndcls.lpszMenuName = NULL;

// Specify your own class name for using FindWindow later
wndcls.lpszClassName = _T("MyNewClass");

// Register the new class and exit if it fails
if(!AfxRegisterClass(&wndcls))
{
TRACE("Class Registration Failed/n");
return FALSE;
}

cs.lpszClass = wndcls.lpszClassName;

return TRUE;
//return CWnd::PreCreateWindow(cs);

BOOL CDialog::Create(LPCTSTR lpszTemplateName, CWnd* pParentWnd)
{
ASSERT(IS_INTRESOURCE(lpszTemplateName) ||
AfxIsValidString(lpszTemplateName));

m_lpszTemplateName = lpszTemplateName; // used for help
if (IS_INTRESOURCE(m_lpszTemplateName) && m_nIDHelp == 0)
m_nIDHelp = LOWORD((DWORD_PTR)m_lpszTemplateName);

#ifdef _DEBUG
if (!_AfxCheckDialogTemplate(lpszTemplateName, FALSE))
{
ASSERT(FALSE); // invalid dialog template name
PostNcDestroy(); // cleanup if Create fails too soon
return FALSE;
}
#endif //_DEBUG

HINSTANCE hInst = AfxFindResourceHandle(lpszTemplateName, RT_DIALOG);
HRSRC hResource = ::FindResource(hInst, lpszTemplateName, RT_DIALOG);
HGLOBAL hTemplate = LoadResource(hInst, hResource);
BOOL bResult = CreateIndirect(hTemplate, pParentWnd, hInst);
FreeResource(hTemplate);

return bResult;
}