Convert modal dialogs to modeless

Many postings to CodeGuru and similar discussion groups are questions about modeless dialogs and how to keep them from blocking the parent thread. I use a user interface thread to start a conventional modal dialog that behaves modeless-ly and it's so minimalist and easy I thought others may be interested...

Instructions

  1. In your header file define a CWinThread-derived class...
      class CDialogThread : public CWinThread { DECLARE_DYNCREATE(CDialogThread) CDialogThread() {}; virtual BOOL InitInstance(); };
  2. Put this in your implementation file (where CSomeDialog is a conventional dialog class defined the usual way).
      IMPLEMENT_DYNCREATE(CDialogThread, CWinThread) BOOL CDialogThread::InitInstance() { CSomeDialog dlg; dlg.DoModal(); return FALSE; }
  3. To create an instance of your (now-modeless) modal dialog, do this...
      AfxBeginThread ( RUNTIME_CLASS(CDialogThread) );
  4. You can end the dialog the normal way by calling CDialog::EndDialog(), CDialog::OnCancel() or CDialog::OnOK(). All those special caveats about modeless dialogs (like "don't call EndDialog") no longer apply with this approach.

  5. One point to note is the return of 'FALSE' from the InitInstance() override. This tells MFC that the thread didn't start successfully, so MFC does our cleanup for us! Note that by this time the dialog has already returned and we're through with the thread. This is the same thing MFC-generated code does in the InitInstance() of dialog-based applications.


Comments

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Live Event Date: February 25, 2015 @ 2:00 p.m. ET / 11:00 a.m. PT Secure Shell (SSH) keys provide unmitigated access for privileged users and applications. However, managing and securing these critical privileged credentials poses a real challenge for organizations, putting sensitive data at risk. In fact, more than 50% of organizations report experiencing an SSH Key related compromise. Check out this upcoming eSeminar and join Adam Bosnian, EVP of Global Business Development at CyberArk, as he discusses the …

  • New IT trends to support worker mobility -- such as VDI and BYOD -- are quickly gaining interest and adoption. But just as with any new trend, there are concerns and pitfalls to avoid. Download this paper to learn the most important considerations to keep in mind for your VDI project.

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date