Re: how to create cwnd in cappthread

From:

"Nick Schultz" <nick.schultz@flir.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 16 Jul 2008 12:33:50 -0700

Message-ID:

<#E13gr35IHA.3784@TK2MSFTNGP06.phx.gbl>

So I passed in the HWND of the window that created the thread (in this case
it is a CDialog), and the application is working (clients are able to
connect, new thread handles connection, packets are being sent, etc) however
I thought it was bad to associate one HWND between two threads. Is what I
did OK, or am I bound for headaches trying to debug?

Nick

"Nick Schultz" <nick.schultz@flir.com> wrote in message
news:%23v1uny25IHA.4448@TK2MSFTNGP05.phx.gbl...

OK so when I try to make the window, I get the error:

Window creation failed: GetLastError returns 0x0000057E

what does this mean?
"David Wilkinson" <no-reply@effisols.com> wrote in message
news:%23nfchN25IHA.4448@TK2MSFTNGP05.phx.gbl...

Nick Schultz wrote:

so I create the cwnd as:

appWnd.CreateEx(0,0,0,0,0,0,0,0,0,0,0);

(here is the function prototype)
virtual BOOL CreateEx(
   DWORD dwExStyle,
   LPCTSTR lpszClassName,
   LPCTSTR lpszWindowName,
   DWORD dwStyle,
   int x,
   int y,
   int nWidth,
   int nHeight,
   HWND hWndParent,
   HMENU nIDorHMenu,
   LPVOID lpParam = NULL
);

I then get a debug assertion error in the CWnd class:

// for child windows
BOOL CWnd::PreCreateWindow(CREATESTRUCT& cs)
{
    if (cs.lpszClass == NULL)
    {
        // make sure the default window class is registered
        VERIFY(AfxDeferRegisterClass(AFX_WND_REG));

        // no WNDCLASS provided - use child window default
        >>>>>>ASSERT(cs.style & WS_CHILD);<<<<<<<
        cs.lpszClass = _afxWnd;
    }
    return TRUE;
}

Nick:

Well, passing WS_CHILD for dwStyle might seem to be a good start. The MFC
code clearly indicates that if the WNDCLASS is NULL, the window must be a
child.

--
David Wilkinson
Visual C++ MVP