in your case, you can put "DoEvents" inside the long calculation/loop
so vba can catch the cancel button events
still it is not asynchronous and it's not the best way, but it's simple

"Robert Mulroney" wrote:

> I just want to be able to a cancel button to a form so users can end a
> calculation if it's taking too long.
>
> "Tim Williams" wrote:
>
> > Robert,
> >
> > I think Excel (in any single instance) is single-threaded, so I'm not surre
> > it supports true asynchronous calls.
> >
> > Tim.
> >
> > --
> > Tim Williams
> > Palo Alto, CA
> >
> >
> > "Robert Mulroney" <''''robert.mulroney@nh.org.au''''> wrote in message
> > news:71B6E447-178F-438F-962E-3AA78B91E412@microsoft.com...
> > > Can anyone point me to a good resource on writing asynchronous procedure
> > > calls? I am particually interested to know if it is possible to do an
> > > asynchronous call on the application.run("") procedure.
> > >
> > > - Rm
> >
> >
> >