Question

I have a MFC CDocument and associated CView open in a MDI application. I would like to detach and close the view (and associated frame), while keeping the document open. Looking around the MFC code to see how it does it, reveals the following in CDocument::OnCloseDocument();

// destroy all frames viewing this document
// the last destroy may destroy us
BOOL bAutoDelete = m_bAutoDelete;
m_bAutoDelete = FALSE;  // don't destroy document while closing views
while (!m_viewList.IsEmpty())
{
    // get frame attached to the view
    CView* pView = (CView*)m_viewList.GetHead();
    ASSERT_VALID(pView);
    CFrameWnd* pFrame = pView->EnsureParentFrame();

    // and close it
    PreCloseFrame(pFrame);
    pFrame->DestroyWindow();
        // will destroy the view as well
}
m_bAutoDelete = bAutoDelete;

which I guess I could use in conjunction with CDocument::RemoveView. Is there a better way to approach this than just lifting the MFC source, and is this approach going to cause me other problems or side effects? The project is VS2010 C++.

Answer 1

If you set CDocument::m_bAutoDelete to FALSE (after the document has been created) it should not delete the document when the last view closes.

I’m not sure what you’re specifically trying to do but you might want to consider creating a separate ‘data’ object that can be attached to a document rather than trying to keep the document itself around.