WM_NCDESTROY的问题,ATL

[夭夭]

template <class TBase>
INT_PTR CALLBACK CDialogImplBaseT< TBase >::DialogProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
CDialogImplBaseT< TBase >* pThis = (CDialogImplBaseT< TBase >*)hWnd;
// set a ptr to this message and save the old value
_ATL_MSG msg(pThis->m_hWnd, uMsg, wParam, lParam);
const _ATL_MSG* pOldMsg = pThis->m_pCurrentMsg;
pThis->m_pCurrentMsg = &msg;
// pass to the message map to process
LRESULT lRes;
BOOL bRet = pThis->ProcessWindowMessage(pThis->m_hWnd, uMsg, wParam, lParam, lRes, 0);
// restore saved value for the current message
ATLASSERT(pThis->m_pCurrentMsg == &msg);
pThis->m_pCurrentMsg = pOldMsg;
// set result if message was handled
if(bRet)
{
switch (uMsg)
{
case WM_COMPAREITEM:
case WM_VKEYTOITEM:
case WM_CHARTOITEM:
case WM_INITDIALOG:
case WM_QUERYDRAGICON:
case WM_CTLCOLORMSGBOX:
case WM_CTLCOLOREDIT:
case WM_CTLCOLORLISTBOX:
case WM_CTLCOLORBTN:
case WM_CTLCOLORDLG:
case WM_CTLCOLORSCROLLBAR:
case WM_CTLCOLORSTATIC:
// return directly
bRet = (BOOL)lRes;
break;
default:
// return in DWL_MSGRESULT
::SetWindowLongPtr(pThis->m_hWnd, DWLP_MSGRESULT, lRes);
break;
}
}
else if(uMsg == WM_NCDESTROY)
{
// mark dialog as destryed
pThis->m_dwState |= WINSTATE_DESTROYED;
}

if((pThis->m_dwState & WINSTATE_DESTROYED) && pThis->m_pCurrentMsg == NULL)
{
// clear out window handle
HWND hWnd = pThis->m_hWnd;
pThis->m_hWnd = NULL;
pThis->m_dwState &= ~WINSTATE_DESTROYED;
// clean up after dialog is destroyed
pThis->OnFinalMessage(hWnd);
}
return bRet;
}
WM_NCDESTROY的消息是由谁来发呀,
如果一个对话框是另一个对话框的子窗口,
那主对话框销..时,了窗口为什么收不到呀.