Waiting for events

[Joel Moore]

I have a long subprocedure that is responsible for controlling a process
on a machine. Essentially, the subprocedure is called when a "Start"
button is pressed and only exits once the process is finished (or
aborted). The process is fairly complicated and involves quite a few
steps. It could look something like this (in VB):

Private Sub ProcessRun()

DigitalOutput(1) = Off
Do While DigitalInput(1) = Off
Application.DoEvents()
Loop

XAxis.MoveTo(3.5)
Do While XAxis.MoveDone = False
Application.DoEvents()
Loop

' etc.

End Sub

only much more complicated. As you can see, I'm using Do While loops
with DoEvents() stuck in the middle to monitor the machine's state. This
works but I can't help thinking this is the wrong way to do things.
Surely there must be a way to apply the event-driven philosophy of
Windows to this process.

So what mechanism should I be looking into to have events raised by my
hardware interface classes (Axes controllers, I/O communications, etc.)
control the progress of ProcessRun()? I picture the following:

Private Sub ProcessRun()

DigitalOutput(1) = Off
WaitForInputOn(1) ' <-- Thread pauses here until Input(1) turns on

XAxis.MoveTo(3.5)
WaitForAxisDone(XAxis) ' <-- Thread pauses here until move is done

' etc.

End Sub

Elegant and resource sparing (I presume). So any suggestions as to how I
can realize this?

I've been looking at ManualEvent and AutoResetEvent. Maybe triggering
one of these from the appropriate event handler. Am I on the right
track?

Joel Moore