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Here is the mystery of the CreateThreadAPI revealed in Jim's post.
http://www.vbforums.com/showthread.p...teThread+pcode
I haven't actually tried it yet, though.
For anyone just looking for an example of using the ActiveX exe way, here is my shortened version of that part of the Coffee example.
Sorry didn't see your post NAVI.
Your program does work... However, it is not initiating the background process itself.... It is waiting for a reponse from the user in the same way all the ones I have writtenm wait for a timer to fire...
How could you use this if say you wanted to, from the client, start a large and complex query against a database, that would be run on another thread?
E.G. In the EXE you have a command button called search.. This creates an object out of the activeX exe, which goes away and searches through thousands of records, on its own thread, without any further input from the user...
The answer is: You can't without a timer...
So what is the deal with using a Timer or not? I mean if it works whats the difference if it uses a timer? Or is this just something that has been bugging you for a while? No offence meant.Quote:
Originally posted by Leather
E.G. In the EXE you have a command button called search.. This creates an object out of the activeX exe, which goes away and searches through thousands of records, on its own thread, without any further input from the user...
The answer is: You can't without a timer...
yap i know wat u on about... but the thing is if we use a timer then whats the point goin through activeX exe? timer in a standerd exe can giv u concurrent processing...Quote:
Originally posted by Leather
E.G. In the EXE you have a command button called search.. This creates an object out of the activeX exe, which goes away and searches through thousands of records, on its own thread, without any further input from the user...
The answer is: You can't without a timer...
in the way i did, once u create the thread u don hav any controle over the thread any more. so u gonna need a outside trriger to run anything on that thread. if u try to trigger anything from the parent thread, dumb VB will atually run the trigger function on parent thread causing ur program to halt.
i havent found any way to control/trigger the thread yet...but i bliv there hav to b a better way than timer.........
Lalalala..la.lalala.lalalalal...la...alala...Use a Message Que...lalalala.la.lalala.lalalalalalalalalalala :DQuote:
Originally posted by Leather
E.G. In the EXE you have a command button called search.. This creates an object out of the activeX exe, which goes away and searches through thousands of records, on its own thread, without any further input from the user...
The answer is: You can't without a timer...
Wokawoof
A Timer in a standard exe wont give you a concurrent process unless you mean the timer itself. In the ActiveX exe the timer is used to create the concurrencly. You notice the first thing in the TimerProc is to kill the timer.
Asynchronous Tasks MSDN near the bottom of the pageQuote:
Originally posted by NAVI_NAVI
i havent found any way to control/trigger the thread yet...but i bliv there hav to b a better way than timer.........
Visual Basic doesn't provide a way to fork execution - that is, to have one thread initiate a method call on a new thread and immediately resume processing on the original thread. You can simulate this behavior in your test application by having the original method call turn on a timer and then return immediately. When the timer event occurs, you can turn the timer off and perform the asynchronous processing. This technique is discussed in "Asynchronous Call-Backs and Events", and is demonstrated (see "Creating an ActiveX Exe Component") and in the Coffee sample application.
S$%t microsot..... n their S$%t VB :mad:
Quote:
Originally posted by honeybee
Hyperspaced, did you take the extreme pains of going through all the posts in this thread? In my first post, I have clearly mentioned you need to use ActiveX EXE and ActiveX DLL or simple EXE to implement a multi-threaded setup. An ActiveX EXE is the only good way of implementing multi-threading in VB. And CreateThread is not at all reliable. Everywhere you go for multithreading in VB6.0, you will find that people will discourage you from using the CreateThread API.
The conclusion is that multithreading in VB is definitely possible, but it doesn't have to be through the CreateThread API. You have to use the ActiveX EXE approach for that.
.
I didn't say that multithreading in VB is impossible.
"Multithreading" meaning like you don't get a 100% multithreaded application
but instead you create multithreaded COMPONENTS, i.e. OLE servers that expose
objects that run on different threads, thus using 'appartment threading' and not
the 'free threading' like in VB.NET and VC++.
Anyway, I don't say that the way you use is incorrect. But understand this :
It is easier to create threads, even in VC++, than on VB6 !!
THAT'S WHY, VB and multithreading don't mix. Very few people use it
(post a poll, I am curious) and I am not one of them, despite the fact
that I consider myself 'a fairly good programmer'.
And something far more basic than programming : Mind your
your 'style'. I am not offended but, trust me,
someone might be. In some more moderated forums you might
have been striked...
Yeap, now you got me !!!!! ;) ;) ;)Quote:
Before jumping to such conclusions that multithreading and VB don't come (actually "go") together, you should get your facts right :rolleyes:
About my style, if you found it a little too harsh, let me apologize. :D
I have been here for more than two years, and have seen all sorts of posts from all people, including from "down under", so don't worry about me being stricken off, and I have always been ready to take a step back if it were my mistake, so I don't think it will ever happen.
Anyways, back to the problem: I am trying to find out a way where you can simply implement the multi-threading model using events, instead of timers.
In the Coffee example in the MSDN, the timer has been used as a replacement for a COM port signal that tells the coffee is ready. It's not used for returning a function call. In fact there's no function call at all in this case. The client simply registers itself as a listener to the coffeemaker, and then the coffee maker notifies the registered listeners when the coffee is ready.
.
Blimey!!!!
What a monster thread this turned into!
Anyway, I believe in we have come to the following points:
1) It is impossible to have VB start a major process on a different thread, even when using ActiveX exe's, without the use of a Timer (VB or API).
2) It is possible to start another thread that essentially waits for some further input, then carries out a process.
I'm glad we got that one cleared up! ; )
:D ;) :p :cool: :rolleyes: :)
How about then...
Create an ActiveX EXE, with a seperate class for each function you want to perform...then in the same activeX EXE you can jhave a form to display data that the class produces...
In your client you can have a picture box and using the setparent API, inside the Class (ActiveX EXE) you can set the parent of the class's form to be the picture box. You can have many of these in one form. Has far as the user is concerned he/she is using a client with one form, but infact it has 2 ActiveX forms embedded into it. Thus, you can control each funtion from the ActiveX forms, and both run in completely different threads :o)
Does that make sence...I am doing a demo of it now, and it works a treat!!!, apart from if I resize the picture box, i can't get the ActiveX EXE's form to resize to fit :( but apart from that it works perfectly...
During you background processing if you have doevents in the loop then you can use a Cancel function to cancel the loop :D
Woka
You know guys, VB.NET is really not hard at all.... and if you had experience with Java before, it'll come alot easier...
what I needed to do was go buy a book made for VB6 Programmers switching over... its not complete (hardly any book ever is), but it does a good job in my opinion..
Visual Basic Programmers Guide to the .NET Framework Class Library
well i'm speakin for myself.. .. i didnt touch VB.NET not coz i thought it'll b hard but coz i don wanna go through any VB c@#p anymore... i lov C/C++ n i'm moving to VC++ n trust me for windows programming VC++ RULES..... and any other kind of programming C/C++ RULES.Quote:
Originally posted by nemaroller
You know guys, VB.NET is really not hard at all.... and if you had experience with Java before, it'll come alot easier...
what I needed to do was go buy a book made for VB6 Programmers switching over... its not complete (hardly any book ever is), but it does a good job in my opinion..
Visual Basic Programmers Guide to the .NET Framework Class Library
:rolleyes:
I actually learned C/C++ on Unix before VB... (still put // everytime i go to comment something), but I never had the initiative to learn Windows programming with it.. (MFC)... but I'll definitely be taking a new look at it with the new VC7 IDE... or at least just go to C#... guess only time will tell where the demand is... but at least VC++ has an intelligent IDE now...
I also learned C/C++ first and when I decided to do some windows programming, I said :
"OK, let's get started with VB first and then I move to VC++"
NOW, I AM STUCK WITH VB !!! I don't know why, it has many limitations, but 99% of the time I get my work done, with less effort (compared to VC++)
Surely, in VB6 not all things are available or easy to do (like multithreading), but in VB.NET things CHANGE DRAMATICALLY.
Since all languages are equal in the .NET Framework (well -- paraphrasing G. Orwell : some languages are slightly more equal than the others -- but that's insignificant) why should I let all the knowledge in VB programming I accumulated over the years go wasted ?
I mean, for 99% of the time, why is VC++ better than VB.NET ?? Performance ?? Maybe, but how much ?? From what I have *heard*, VC++ is not much faster than VB.NET.
(If anyone has more detailed info about the performance, please share it with the rest)
Anyway, my conclusion : The project I am currently working is the last on VB6. I am going VB.NET from now on. It's not much of a choice. More like a need, it seems to me.
Book suggestion : I bought "Programming VB.NET -- A Guide for Experienced Programmers" by Gary Cornell, which I think is a very good intoduction to VB.NET
I am also thinking of buying "Programming Microsoft VB.NET (Core Reference)" by Francesco Balena. Does anyone know if it's worth it ??
--hyperspaced
That is a very good book. I would highly recommend it. It covers just about everything although you might wish that somethings where in detail more. It doesn't really walk you through a step by step on everything because it covers so much but as long as you aren't a beginner to programming as a whole then you'll be fine. Two thumbs up says Ed Marquez.;)
here's a quick small multi thread example...using ActiveX EXE's...It's a bit rough round the ages, but basically I can't be arsed to use correct name varibles and so on...
What you have to do, is load the project EmbeddedExample, and compile it to an ActiveX EXE, then close it. Then Load TestProject and reference EmbeddedExample that u have just compiled, then run the project.
U will see 2 seperate counting threads and a timer on the main form. U can set anything to be the parent of the objects so long as you have a windows handle...
Just goes to show VB can handle multithreadding quite well :D
Any tips or adeas would be greatly appreciated...
Woka
Also, with that project I have written you can the the following...to make it pure multitasking :D
http://www.vbforums.com/showthread.p...52#post1197852
Although this example is for a search string, and my objects don't do a search, but it's the prinipal that I am looking at...
Woka
Check out the link in my sig.
Multithreading sorted :D
Woof
Just for information, if it hasn't been mentioned before - it is possible to explicitly create threads in VB, i.e. with CreateThread(). It isn't easy to do safely, because of VB's tight interaction with COM, but it can be done.
MS says that using CreateThread API is bad.
My example doesn't use CreateThread.
Woka
Define "bad". MS isn't always right.
Another problem, many people will completely misapply MT - in a lot of situations, it isn't appropriate or useful, though I'd bet people still do MT for some "cool" factor.
I suspect this is why MS made MT in VB6 limited and not easy; VB is used by many programmers who don't have the experience/interest to learn about the consequences of MT.
COM is a right pain in this case, it clouds the issues.
Fair do's.
MT in VB6 using CreateThread is dodgy and applications crash.
Find me a good example where this doesn't happen...coz I ain't found one yet, neither has anyone else I know.
Woka
Have a read of Matt Curland's excellent "Advanced Visual Basic 6", published by Addison-Wesley. Lots of good stuff in there, including threading. Really gets "behind the scenes" of VB and COM.