How to Create a CMDIFrameWnd in dll with doc/view

Now we could try to analyze the type of pMDIFrame... :)

This is the code export from dll:

// global function exports so we can be loaded by DLL
extern "C" __declspec( dllexport ) CMyMultiDocTemplate* DLLDocTemplate()
{
    // create the CMyMultiDocTemplate object to pass to exe
    // we have to be using the local resources when we do this as
    // the CDocTemplate constructor calls LoadTemplate() before the
    // vtable for virtual functions is setup and calls the base
    // class implementation
    AFX_MANAGE_STATE(AfxGetStaticModuleState()) ;
    CMyMultiDocTemplate *pTemplate = NULL ;
    pTemplate = new CMyMultiDocTemplate(
        theApp.m_hInstance,         // the APP's resource instance
        IDR_DLLDOCUMENT,
        RUNTIME_CLASS(CDLLDocument),
        RUNTIME_CLASS(CDLLChildFrame), // custom MDI child frame
        RUNTIME_CLASS(CDLLDocumentView));
    return pTemplate ;
}
extern "C" __declspec( dllexport ) BOOL CreateDllFrame()
{
    if ( theApp.m_pMainWnd == NULL )
    {
        AFX_MANAGE_STATE(AfxGetStaticModuleState()) ;
        CDLLMainFrame* pMainFrame = new CDLLMainFrame;
        if (!pMainFrame->LoadFrame(IDR_DLLDOCUMENT))
            return FALSE;
        theApp.m_pMainWnd = pMainFrame;
        pMainFrame->ShowWindow( SW_SHOW );
        pMainFrame->UpdateWindow();
    }
    return TRUE;
}

dll have it's own DocTemplate and I have overwrite the two function:

void CMyMultiDocTemplate::LoadTemplate()
{
	// call the base class member after switching the resource to the DLL, if this is a DLL document type
	HINSTANCE	hOld ;

	hOld = AfxGetResourceHandle() ;			// save
	AfxSetResourceHandle(m_hInst) ;			// set
	CMultiDocTemplate::LoadTemplate() ;		// now get from correct resources!
	AfxSetResourceHandle(hOld) ;			// restore
}

CDocument* CMyMultiDocTemplate::OpenDocumentFile(LPCTSTR lpszPathName, BOOL bMakeVisible)
{
	// switch to the correct resources and then resturn the document
	CDocument	*pDoc = NULL ;
	HINSTANCE	hOld ;

	hOld = AfxGetResourceHandle() ;			// save
	AfxSetResourceHandle(m_hInst) ;			// set
	//CreateDllFrame();
	pDoc = CMultiDocTemplate::OpenDocumentFile(lpszPathName, bMakeVisible) ;
	AfxSetResourceHandle(hOld) ;			// restore
	return pDoc ;
}

I AddDocTemplate() and CreateDllFrame() in exe app's InitInstance()

Please post the definition of CDLLMainFrame :)

//DLLMainFrm.h
class CDLLMainFrame : public CMDIFrameWnd
{
	DECLARE_DYNAMIC(CDLLMainFrame)
public:
	CDLLMainFrame();

// Attributes
public:

// Operations
public:

// Overrides
	// ClassWizard generated virtual function overrides
	//{{AFX_VIRTUAL(CDLLMainFrame)
	virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
	//}}AFX_VIRTUAL

// Implementation
public:
	virtual ~CDLLMainFrame();
#ifdef _DEBUG
	virtual void AssertValid() const;
	virtual void Dump(CDumpContext& dc) const;
#endif

protected:  // control bar embedded members
	CStatusBar  m_wndStatusBar;
	CToolBar    m_wndToolBar;

// Generated message map functions
protected:
	//{{AFX_MSG(CDLLMainFrame)
	afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct);
		// NOTE - the ClassWizard will add and remove member functions here.
		//    DO NOT EDIT what you see in these blocks of generated code!
	//}}AFX_MSG
	DECLARE_MESSAGE_MAP()
};

//DLLMainFrm.cpp
/////////////////////////////////////////////////////////////////////////////
// CDLLMainFrame

IMPLEMENT_DYNAMIC(CDLLMainFrame, CMDIFrameWnd)

BEGIN_MESSAGE_MAP(CDLLMainFrame, CMDIFrameWnd)
	//{{AFX_MSG_MAP(CDLLMainFrame)
		// NOTE - the ClassWizard will add and remove mapping macros here.
		//    DO NOT EDIT what you see in these blocks of generated code !
	ON_WM_CREATE()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

static UINT indicators[] =
{
	ID_SEPARATOR,           // status line indicator
	ID_INDICATOR_CAPS,
	ID_INDICATOR_NUM,
	ID_INDICATOR_SCRL,
};

/////////////////////////////////////////////////////////////////////////////
// CDLLMainFrame construction/destruction

CDLLMainFrame::CDLLMainFrame()
{
	// TODO: add member initialization code here
	
}

CDLLMainFrame::~CDLLMainFrame()
{
}

int CDLLMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
	if (CMDIFrameWnd::OnCreate(lpCreateStruct) == -1)
		return -1;
	
	if (!m_wndToolBar.CreateEx(this, TBSTYLE_FLAT, WS_CHILD | WS_VISIBLE | CBRS_TOP
		| CBRS_GRIPPER | CBRS_TOOLTIPS | CBRS_FLYBY | CBRS_SIZE_DYNAMIC) ||
		!m_wndToolBar.LoadToolBar(IDR_DLLFRAME))
	{
		TRACE0("Failed to create toolbar\n");
		return -1;      // fail to create
	}

	if (!m_wndStatusBar.Create(this) ||
		!m_wndStatusBar.SetIndicators(indicators,
		  sizeof(indicators)/sizeof(UINT)))
	{
		TRACE0("Failed to create status bar\n");
		return -1;      // fail to create
	}

	// TODO: Delete these three lines if you don't want the toolbar to
	//  be dockable
	m_wndToolBar.EnableDocking(CBRS_ALIGN_ANY);
	EnableDocking(CBRS_ALIGN_ANY);
	DockControlBar(&m_wndToolBar);

	return 0;
}

BOOL CDLLMainFrame::PreCreateWindow(CREATESTRUCT& cs)
{
	if( !CMDIFrameWnd::PreCreateWindow(cs) )
		return FALSE;
	// TODO: Modify the Window class or styles here by modifying
	//  the CREATESTRUCT cs

	return TRUE;
}

It seems to be OK :)

Now -
please obeserve the stack (post it) at the assertion stopping
and the type of pMDIFrame (just move your cursor there) :)

CDLLMainFrm is a class I copy from exe's CMainFrm.

When I created the main frame in exe, it work and the child frame defined in dll was showed correctly in this main frame, but when i created the main frame in dll, the problem came again.

please obeserve the stack (post it) at the assertion stopping
and the type of pMDIFrame (just move your cursor there)

I did, and I found the type of pMDIFrame was CWnd, and the value of hWnd and m_hWnd is different, I guess this may be the point.

OK, now we have the reason of the assertion :)

And the stack at the assertion,
could you post it, please ?

mfc90ud.dll!CMDIChildWnd::GetMDIFrame()  行901   C++
mfc90ud.dll!CMDIChildWnd::OnSize(unsigned int nType=0, int cx=786, int cy=385)  行631 + 0x8 字节   C++
mfc90ud.dll!CWnd::OnWndMsg(unsigned int message=5, unsigned int wParam=0, long lParam=25232146, long * pResult=0x0012e5e4)  行2066   C++
mfc90ud.dll!CWnd::WindowProc(unsigned int message=5, unsigned int wParam=0, long lParam=25232146)  行1755 + 0x20 字节  C++
mfc90ud.dll!AfxCallWndProc(CWnd * pWnd=0x00ec62e0, HWND__ * hWnd=0x001408f6, unsigned int nMsg=5, unsigned int wParam=0, long lParam=25232146)  行240 + 0x1c 字节  C++
mfc90ud.dll!AfxWndProc(HWND__ * hWnd=0x001408f6, unsigned int nMsg=5, unsigned int wParam=0, long lParam=25232146)  行403    C++
mfc90ud.dll!AfxWndProcBase(HWND__ * hWnd=0x001408f6, unsigned int nMsg=5, unsigned int wParam=0, long lParam=25232146)  行441 + 0x15 字节  C++
user32.dll!7e418734()
user32.dll!7e418816()
user32.dll!7e42bf15()
user32.dll!7e430b05()
user32.dll!7e430a5f()
mfc90ud.dll!CMDIChildWnd::DefWindowProcW(unsigned int nMsg=71, unsigned int wParam=0, long lParam=1239836)  行429    C++
mfc90ud.dll!CWnd::WindowProc(unsigned int message=71, unsigned int wParam=0, long lParam=1239836)  行1756 + 0x1c 字节  C++
mfc90ud.dll!AfxCallWndProc(CWnd * pWnd=0x00ec62e0, HWND__ * hWnd=0x001408f6, unsigned int nMsg=71, unsigned int wParam=0, long lParam=1239836)  行240 + 0x1c 字节  C++
mfc90ud.dll!AfxWndProc(HWND__ * hWnd=0x001408f6, unsigned int nMsg=71, unsigned int wParam=0, long lParam=1239836)  行403    C++
mfc90ud.dll!AfxWndProcBase(HWND__ * hWnd=0x001408f6, unsigned int nMsg=71, unsigned int wParam=0, long lParam=1239836)  行441 + 0x15 字节  C++
user32.dll!7e418734()
user32.dll!7e42bdf1()
user32.dll!7e42bf90()
user32.dll!7e42be3b()
ntdll.dll!7c90e473()
user32.dll!7e4299ff()
mfc90ud.dll!_AfxModifyStyle(HWND__ * hWnd=0x92840f00, int nStyleOffset=-1191182606, unsigned long dwRemove=32768, unsigned long dwAdd=4277307625, unsigned int nFlags=2425393407)  行104 C++
008005f9()

- pMDIFrame 0x003adff0 {CWnd hWnd=0x0009085a} CMDIFrameWnd *
+ [CWnd] {CWnd hWnd=0x0009085a} CWnd
+ CFrameWnd {CFrameWnd hWnd=0x0009085a} CFrameWnd
- classCMDIFrameWnd {"CMDIFrameWnd"} const CRuntimeClass
+ m_lpszClassName 0x789e6054 "CMDIFrameWnd" const char *
m_nObjectSize 236 int
m_wSchema 65535 unsigned int
m_pfnCreateObject 0x78a58890 CMDIFrameWnd::CreateObject(void) CObject * (void)*
m_pfnGetBaseClass 0x78a589d0 CMDIChildWnd::_GetBaseClass(void) CRuntimeClass * (void)*
+ m_pNextClass 0x00000000 {???} CRuntimeClass *
+ m_pClassInit 0x00000000 const AFX_CLASSINIT *
+ m_hWndMDIClient 0xcdcdcdcd {unused=??? } HWND__ *
+ this 0x00ec62e0 {CDLLChildFrame hWnd=0x00080874} CMDIChildWnd * const

Please set a breakpoint in the same file of the assertion at:

BOOL CMDIChildWnd::Create(LPCTSTR lpszClassName,
	LPCTSTR lpszWindowName, DWORD dwStyle,
	const RECT& rect, CMDIFrameWnd* pParentWnd,
	CCreateContext* pContext)
{ // set breakpoint here...

...then start the debugger and take a stop for your DLL child creation:
is the pParentWnd of the valid type there ? :)

The "bug" has been found :-D :

please overwrite the:

CDocument* CMultiDocTemplate::OpenDocumentFile(LPCTSTR lpszPathName,
	                                      BOOL bMakeVisible)

to pass your parent pointer (and not NULL) to CreateNewFrame(.., !!!) inside :)

Thank you! :)

I overwrited CDLLChildFrame::Create() like that:

CDLLChildFrame::Create(LPCTSTR lpszClassName,	LPCTSTR lpszWindowName, DWORD dwStyle,	const RECT& rect, CMDIFrameWnd* pParentWnd,	CCreateContext* pContext)
{
    if(pParentWnd==NULL)
    {
        pParentWnd =  (CMDIFrameWnd*)theApp.m_pMainWnd;
    }
    CMDIChildWnd::Create(lpszClassName,	lpszWindowName, dwStyle,rect, pParentWnd,pContext);
}

and it pop the message:"failed to create empty document"

and when I put this code in the CDLLChildFrame::LoadFrame() when overwrited it, it got the problem I said in my question.

I found the solution.

The reason may be I call too much

AFX_MANAGE_STATE(AfxGetStaticModuleState()) ;

\


I replace AFX_MANAGE_STATE(AfxGetStaticModuleState()) ; by these code:

HINSTANCE   hOld ;
hOld = AfxGetResourceHandle() ;         // save
AfxSetResourceHandle(m_hInst) ;         // set
//Here I create the frame
AfxSetResourceHandle(hOld) ;            // restore

and the bug had disappeared, but I don't know why, so welcome any explanations for it