asked on

Multithreading... maybe -- Hard to explain

I don't know what I need, but here is my current problem:

I would like to make an object (ActiveX or user control, or whatever) that has a method which loops for a few seconds, such as:

private sub methodname()

for i = 1 to 100
'code
doevents
sleep 10
next i

end sub

This works fine. However, if I put 2 of these objects on a form (call them object1 and object2) and run this code:

object1.methodname
object2.methodname

Visual Basic waits for object1 to finish running the sub "methodname" before moving on to object2

How can I get them to run their procedures at the same time?

If this is hard to understand, please let me know what else you would like me to include.

Thanks,
-Sam

ameba

> object1.methodname
> object2.methodname

If you have those two line in one procedure, first will run the first procedure, then after it has finished, the second.

Start your task(s) asynchronously, e.g. here is a simple way using a timer (Interval = 1):

Private Sub cmdStart()
' create objects
' ...
Timer1.Enabled = True ' this will start the first task
object2.methodname
End Sub

Private Sub Timer1_Timer()
object1.methodname
Timer1.Enabled = False
End Sub

> sleep 10
This will Not give more time to the second task in the same process, but to other applications and to Windows.
To run your tasks smoothly, add enough DoEvents lines (e.g. 10 DoEvents per second).

xSinbad

Here are some links that may help you with multi treading;

http://www.desaware.com/articles/threadingL3.htm

http://www.desaware.com/articles/Waitingl3.htm

http://planetsourcecode.com/vb/scripts/ShowCode.asp?txtCodeId=26900&lngWId=1

http://planetsourcecode.com/vb/scripts/ShowCode.asp?txtCodeId=24672&lngWId=1

http://planetsourcecode.com/vb/scripts/ShowCode.asp?txtCodeId=14479&lngWId=1

samsonite1023

ASKER

The "Sleep 10" command is there because the loop will be performing a visual animation with the control (moving it, fading it). Is there a better way to do this?

ameba

Than it's OK to use "Sleep 10"

samsonite1023

ASKER

I just tried out your suggested code, the same thing happens. It seems like once it gets into the loop, everything stops until it gets done it.

Any other things I could try?

ameba

Maybe your loop period lasts too long, or there isn't enough DoEvents.
I know it works. The other things, like threading are maybe too complex.

If you want, I can create sample, e.g. two long calculations running at the same time, and each updating one label on the form.

ASKER CERTIFIED SOLUTION

mdougan

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samsonite1023

ASKER

Thanks for the info!

mdougan

Thanks. Since my last post, I've downloaded a sample multi-treading vb program using CreateThread that didn't crash under VB6.... this is very odd, because I'd had a sample that crashed under VB6 every time, but worked fine under VB5, using the same API. Now, I know it was crashing under W2K, and here I'm testing on NT 4.0, so, I don't know if that makes a difference or not.

If you are interested in a sample to try, let me know. It would help if you posted an e-mail address, and I can forward a zip of a project.