Re: Question on Progress dialog

"AliR \(VC++ MVP\)" <AliR@online.nospam>
Thu, 24 Jan 2008 18:35:31 GMT
"David Ching" <> wrote in message

"AliR (VC++ MVP)" <AliR@online.nospam> wrote in message

A more elegant solution (IMHO) would be to use a base class for any class
that want's to use your progress control, which has a virtual function
(perhaps even pure virtual) that gets called when the user presses the
cancel key.

class CProgressBarReceiver
   virtual void OnCancel() = NULL;

class CProgressDialog : public CDialog
   CProgressDialog(CProgressBarReceiver *pNotifyParent......);
   void SetNotifyParent(CProgressBarReceiver *pNotifyParent);

class CMyDocument : public CDocument, public CProgressBarReceiver
   virtual void OnCancel() { CloseDialog(); KillThread();
CloseDocument(); }

I suppose it's more elegant, but my personal preference because I value
terseness and ease of use is not to do it this way. Any caller can easily
create a static callback function, but forcing the caller to derive from
your class just to receive progress messages is a philosophy that leads to
massive class hierarchies that are not easily grok'd.

-- David

What about addressing the problem of having to have a static method. You
won't be able to distinguish between different instances of the class.
Sometime the easy way might not fulfill every need, that's what I was
pointing out.


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