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  • Your email address will not be published.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

  • U.S. companies are desperately trying to recruit and hire skilled software engineers and developers, but there is simply not enough quality talent to go around. Tiempo Development is a nearshore software development company. Our headquarters are in AZ, but we are a pioneer and leader in outsourcing to Mexico, based on our three software development centers there. We have a proven process and we are experts at providing our customers with powerful solutions. We transform ideas into reality.

  • By providing developers with the right tools to detect, understand, and fix problems early, your business can simplify software development, shorten development lifecycles, and improve the quality of software code. The end result is increased innovation, secure applications, and a faster time to market — all at a lower cost.

Most Popular Programming Stories

More for Developers

RSS Feeds

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