Can't create modal dialog from MFC DLL

I'm trying to launch a modal dialog from a DLL loaded by an MFC application. I'm using VS2010 and both the EXE and DLL use MFC in a static library.

I call DoModal() in my DLL to launch the dialog, with the parent being a CWnd* pointing to the main window from the MFC app. The dialog resource is in the DLL.

This eventually leads to the MFC library function CWnd::CreateDlgIndirect, which has this debug check:

#ifdef _DEBUG
    if ( AfxGetApp()->IsKindOf( RUNTIME_CLASS( COleControlModule ) ) )
    {
        TRACE(traceAppMsg, 0, "Warning: Creating dialog from within a COleControlModule application is not a supported scenario.\n");
    }
#endif

AfxGetApp() returns NULL so the code in the debug check fails. If I compile in release, the dialog appears, but doesn't seem to work (all the fields are empty even though I set defaults, some button's don't appear).

I've tried adding AFX_MANAGE_STATE(AfxGetStaticModuleState()); t开发者_StackOverflow中文版o the top of the function that launches the dialog, and it doesn't make any difference.

What am I missing?

Edit: here's the code I use to call the dialog.

HMODULE oldResMod = AfxGetResourceHandle();

AFX_MANAGE_STATE(AfxGetStaticModuleState());
AfxSetResourceHandle(GetThisModule());

CWnd wndParent;
wndParent.Attach(parent);

CExportOptionsDlg dlg(&wndParent);
dlg.project_name = project->GetName();

if (dlg.DoModal() != IDOK)
{
    wndParent.Detach();
    AfxSetResourceHandle(oldResMod);
    return false;       // cancelled
}

// ... (get some data from the dialog members) ...

wndParent.Detach();
AfxSetResourceHandle(oldResMod);
return true;            // OK

---

Check that you've actually created a CWinApp somewhere in your current module (DLL/EXE).

Every module should have one, and only one, CWinApp object. Typically, you would make the CWinApp object a global variable such that it is created and destroyed when the module is loaded and unloaded, respectively.