How do I pass an event to a thread

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Hi,

I have a stock dataFeed that has an event that fires approx 4 or 5 times per sec sending the stock data via a event arg. I parse the event arg and insert the results into a database via a database object that wrote. All of this activity seems to overwhelm the windows form and consumes most of system resources. I'd like to put the stock dataFeed event on a thread but I don't know how. I've tried creating a ThreadStart object and using an anonymous delegate to pass the event to but I dont know how to instantiate the event arg or what object to pass...

example:

C#

// dataFeed event
private void stockDataFeed(object sender, stockDataFeedArg arg)
{
   myDatabaseOject.Insert(arg.stockPrice);
}

private void Button_Click(object sender, EventArgs e)
{
   ThreadStart tS = delegate() {stockDataFeed(?,?);};
   Thread t = new Thread(tS);
   t.Start();
}

Can some one please explain/show me what I'm doing wrong and what's the correct way to go about this.

Thanks!

-Donald

Posted 26-Jan-11 15:38pm

d.allen101

Updated 26-Jan-11 15:44pm

v3

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Dave Kreskowiak · Answer 1 · 2011-01-26T15:59:00

Solution 1

You don't create a new thread on every event. Creating a thread is a very expensive process.

Instead, I'd probably look into adding the data to a queue in your event handler. A second thread, that you start at the beginning of your code, NOT in the event handler, watches this queue for items to process and add to the database. When it's done processing items, it falls asleep for x number of seconds before waking up and checking the queue again.

Posted 26-Jan-11 15:59pm

Dave Kreskowiak

Comments

Sergey Alexandrovich Kryukov 26-Jan-11 22:04pm

Totally agree - my 5. I covered this issue in my answers to OP's previous question. I don't know why my advice was ignored. I also provided complete samples for inter-thread invocation. As you can see, I even posted a Tip as a permanent reference, as many Questions could be resolved using this technique.

Thank you.
--SA

d.allen101 26-Jan-11 22:18pm

ok, so you're saying have a queue object inside the dataFeed event thats enqueuing the feed args and the queue is being "watched" by a thread which is dequeuing the results into my database object and it's (the thread watching the queue) sleeping for a second or so after each dequeue?

d.allen101 26-Jan-11 22:20pm

hey SAKryukov, I'm not ignoring your advice, I'm just having trouble grasping this...I'm a novice dev and no experience with using delegates and threads.

Sergey Alexandrovich Kryukov 26-Jan-11 23:52pm

Sorry Donald, I understand. The reason I felt you ignored was that you did not ask about inter-thread invocation in the comment to my second answer to your previous Question but created a new Question. In fact, I expected your feedback and checked that page from time to time. My guess was that you overlooked my words about that techniques. I did not see a big problem in it -- it happens to me all the time and later I fix myself. Same thing with you. Please don't get it personally or as a blame. You can see that I readily continued to answer to your problems -- on this new page. You know that I replied to your follow-up questions in detail.
Also, don't hesitate to ask if you have further questions. I can imagine how difficult is to grasp all that matter if you did not collect a lot of experience on more simple problems.
Best,
--SA

d.allen101 26-Jan-11 23:58pm

NOOO! it's not that at all SAKryukov, you helped me out last time! it's just that I'm not familiar with threads and delegates...you have to be a little patient with me until I get up to speed. you've responded to EVERY single thread I've posted about multi-threading and you've helped me out alot but I need a little more explanation and simple examples...

Sergey Alexandrovich Kryukov 27-Jan-11 0:46am

Donald, I know you paid a lot of attention. What I like is that you try to understand "why", which is the only productive approach. I explained myself. I also don't think you could complain I did not exercise patience :-)
I think we're good. :-)
Again, all your questions are welcome and would be happy if you make a good project.
Best,
--SA

Sergey Alexandrovich Kryukov 27-Jan-11 0:48am

Donald, by the way, steer discussion to my answer. I just realize this is Dave's thread. I can imagine his irritation after getting e-mail notification of all that...

Sorry, Dave!
--SA

Sergey Alexandrovich Kryukov · Answer 2 · 2011-01-26T16:03:00

Solution 2

Donald, it might surprise you, but the precise answer to this question is contained in my second answer to you previous question.

All you need it to read the last code sample from my Article from Tips/Tricks section:

Simple Blocking Queue for Thread Communication and Inter-thread Invocation[^].

See also Alternative Tip to my article and related Microsoft sample (v.4.0 only, while I provide a solution good for all Framework versions 2.0 and later).
This last sample shows how to organize inter-thread invocation. You can use this code with very minimal changes: just instantiate generic with your event argument type.

Further questions are welcome.

Good luck!

—SA

Posted 26-Jan-11 16:03pm

Sergey Alexandrovich Kryukov

Updated 26-Jan-11 17:30pm

v3

Comments

d.allen101 26-Jan-11 22:21pm

Ok thanks, i'm about to read it RIGHT now!

Espen Harlinn 27-Jan-11 14:27pm

5+ Good effort, it's turning into a series :)

Sergey Alexandrovich Kryukov 27-Jan-11 23:39pm

Thank you, Espen,
I recently found yet another publication, very promising to turn into series as well, because it is even more universal :-)
Please see: "http://radio-weblogs.com/0001263/junk/Q209354 - HOWTO.html".
I already used it in comments and -- in particular -- in one of my today's answers.

Thank you,
--SA

Espen Harlinn 28-Jan-11 14:08pm

Good one :) - and a few more:
RTBM ("read the bloody manual")
RTFA ("read the f***ing article")
RTFE ("read the f***ing e-mail")
RTFC ("read the f***ing code" [also "reboot the f***ing computer"])
RTFSC ("read the f***ing source code")
RTFQ ("read the f***ing question")
RTFFAQ ("read the f***ing frequently asked questions")
UTFH ("use the f***ing help")
UTSL ("use the source, Luke")
JFWI ("just f***ing Wiki it")
JGIYN ("just Google it, you noob")
STFG ("search the f***ing Google")
STFW ("search the f***ing Web")
WIDGI ("when in doubt, Google it")

Might come handy when answering questions :)

Sergey Alexandrovich Kryukov 28-Jan-11 14:18pm

Yes, a good list, by the way.
You don' really need those ***stars***:
The canonical way of saying is this:
"RTFM -- Read The Following ;-) Manual".

--SA

Espen Harlinn 28-Jan-11 16:45pm

Try writing the f***ing f word here on CP en see what happens :)

Sergey Alexandrovich Kryukov 28-Jan-11 20:03pm

I actually like elegant euphemism. Let me tell you one story.

Many years ago a friend of mine, a very talented guy, in some emotional funny argument in a company suddenly hurled at his opponent the following :-) phrase:
"If you can't think, don't torture your head!".
I don't remember we ever laughed so loud!

Now, what's so funny?

Understanding of this requires some background. There is one "taboo" proverb actually very popular in all the folks, with the meaning: "stop trying, you're incapable of doing such things". Absolutely everyone knows this proverb very well, and some (touch) people never miss a chance to use it. In translation, it would sound literally like this:
"If you cannot... well, have constipation, don’t torture your..."... well, you understand...

Regards,
--SA

Espen Harlinn 29-Jan-11 2:32am

ahh, yes :)