Question

I’m facing some weird (at least for me) behavior on using the Common Item Dialogs in my MFC Windows application running on Windows 7 or Vista.

According to the MSDN http://msdn.microsoft.com/en-us/library/windows/desktop/bb776913(v=vs.85).aspx I’m using the new interfaces to display file open and save dialogs:

bool OpenFileDialog(CString& strFile, CString strTitle, CStringArray& astrFilter, CStringArray& astrFilterExtension, ULONG nFlags, HWND hParentWnd)
{
USES_CONVERSION;

INT_PTR  nResult = 0;
INT_PTR  nFilterCount = astrFilter.GetCount();

IFileDialog* pfod = 0;
HRESULT hr = ::CoCreateInstance(CLSID_FileOpenDialog, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pfod));

if(SUCCEEDED(hr))
{
    // New dialog starting with Vista/Windows 7
    COMDLG_FILTERSPEC*  pOpenTypes = 0;

    if((nFilterCount > 0) && (nFilterCount == astrFilterExtension.GetCount()))
    {
        pOpenTypes = new COMDLG_FILTERSPEC[nFilterCount];

        for(int nIdx = 0; nIdx < nFilterCount; nIdx++)
        {
            pOpenTypes[nIdx].pszName = astrFilter[nIdx].GetBuffer();
            pOpenTypes[nIdx].pszSpec = astrFilterExtension[nIdx].GetBuffer();
        }
    }

    // Set the file types to display.
    if(pOpenTypes)
    {
        hr = pfod->SetFileTypes(nFilterCount, pOpenTypes);

        if(SUCCEEDED(hr))
            hr = pfod->SetFileTypeIndex(0);
    }

    if(!strFile.IsEmpty())
        pfod->SetFileName(strFile);

    if(!strTitle.IsEmpty())
        pfod->SetTitle(strTitle);

    if(SUCCEEDED(hr))
    {
        // Ensure the dialog only returns file system paths.
        DWORD dwFlags;
        hr = pfod->GetOptions(&dwFlags);

        if(SUCCEEDED(hr))
        {
            dwFlags |= FOS_FORCEFILESYSTEM;

            if(nFlags & OFN_FILEMUSTEXIST)
                dwFlags |= FOS_FILEMUSTEXIST;

            if(nFlags & OFN_PATHMUSTEXIST)
                dwFlags |= FOS_PATHMUSTEXIST;

            hr = pfod->SetOptions(dwFlags);

            if(SUCCEEDED(hr))
            {
                // Create an event handling object, and hook it up to the dialog.
                IFileDialogEvents*  pfde = NULL;
                DWORD dwCookie;

                // Actually only added for debugging purposes

                /*hr = CDialogEventHandler_CreateInstance(IID_PPV_ARGS(&pfde));

                if(SUCCEEDED(hr))
                {
                    // Hook up the event handler.
                    hr = pfod->Advise(pfde, &dwCookie);

                    if(!SUCCEEDED(hr))
                    {
                        pfde->Release();
                        pfde = 0;
                    }
                }*/

                // Now show the dialog. Usually called with hParent == 0
                if(hParentWnd)
                    hr = pfod->Show(::GetWindow(hParentWnd, GW_OWNER));
                else
                    hr = pfod->Show(0);

                // do something with the path when the dialog was closed...

So the dialog appears and works fine if I want to select a file from a normal drive. I can navigate through the folders and select any file I want. On leaving the dialog I also get the correct file information.

But it doesn’t work for one of the Libraries in the navigation pane on the left side. Whenever I try to select a Library like Documents, Videos or Pictures the dialog doesn’t update the right pane which shows the folder/library content.

What I noticed is that on clicking a Library in the file open/save dialog the OnFolderChanging() event of the IFileDialogEvents interface is fired but the OnFolderChange() and OnSelectionChange() are not. Those events are fired if I click and navigate on a “normal” drive like C.

I also tried to call the dialogs early in my InitInstance method to avoid possible side-effects with my other code but this didn’t help either.

Is there someone who had the same behavior and was able to resolve this?

Thanks a lot!

Answer 1

So I finally found the answer to this issue. Creating the new MFC project for the application was the actual hint to solve this. The reason was that the “Stack reserve size” was too big. The settings in the old VS6.0 project had the stack size increased to more than 100MB. Apparently the IFileDialog based dialogs do not work properly when the reserved stack size is simply too large (other thing might don’t work also as expected). So I had to set it back to 15MB in my case.