PRB: OnClose() Is Called When Closing Print Preview Dialog Box

RESOLUTION

In your OnClose() function, you do not want to do the same processing during a Print Preview close that you do during an application close. Therefore, you should make a special case in the OnClose() code to check whether or not it is being called from Print Preview.

The following code demonstrates how to modify the OnClose() to do nothing during the Print Preview close.

void CMainFrame::OnClose()
    {
    if (m_bPreview ||
       (AfxMessageBox(ID_EXIT_PROMPT, MB_YESNO) == IDYES))
        {
        CFrameWnd::OnClose();
        }
    }
				

In this example, ID_EXIT_PROMPT is a string table resource containing the string that you want to display in the message box. In addition, m_bPreview is a member that you need to add to the CMainFrame class; it is initialized to FALSE in the constructor of the CMainFrame class. Then, the m_bPreview variable is set again using an override of CFrameWnd::OnSetPreviewMode().

// In .h file of CMainFrame class:
class CMainFrame : public CFrameWnd
    {
    BOOL m_bPreview;  // TRUE in print preview mode; FALSE otherwise
    ...
    };

// In .cpp file of CMainFrame class:
CMainFrame::CMainFrame()
    {
    m_bPreview = FALSE;
    }


void CMainFrame::OnSetPreviewMode(
    BOOL bPreview, CPrintPreviewState* pModeStuff)

    {
    m_bPreview = bPreview;
    CFrameWnd::OnSetPreviewMode(bPreview, pModeStuff);
    }