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How to raise async eventsI am working on a c# project using framework 1.1. Since its a console application,no windows forms are being used. I am trying to implement event driven classes that just want to raise the event and continue working( like fire and forget - do not wait for the event handler in client to finish.) I have gone through alot of the articles on internet and MSDN and most talk about delegates (or BackGroundWorker in 2.0 which I cannot use.) all the other solutions out there are for classes raisng async events for windows forms in one way or the other. I am interested in a solution that allows two classes that do not inherit from Control class and raise events and work togather in async fashion. I will really appreciate if some one can help me with this. Thanks, Nad You could use System.Threading.Thread class to start another method in
a new thread. You can raise an event as normal from this thread using a delegate. nadeem_***@yahoo.com wrote: Show quote > Hello, > > I am working on a c# project using framework 1.1. > Since its a console application,no windows forms are being used. > I am trying to implement event driven classes that just want to raise > the event and continue working( like fire and forget - do not wait for > the event handler in client to finish.) > > I have gone through alot of the articles on internet and MSDN and most > talk about delegates (or BackGroundWorker in 2.0 which I cannot > use.) all the other solutions out there are for classes raisng async > events for windows forms in one way or the other. > > I am interested in a solution that allows two classes that do not > inherit from Control class and raise events and work togather in async > fashion. > > I will really appreciate if some one can help me with this. > > Thanks, > > Nad Hi,
-- Ignacio Machin http://www.laceupsolutions.com Mobile & warehouse Solutions. <nadeem_***@yahoo.com> wrote in message news:4471a130-48b7-40d4-a9c7-4946bc942997@i12g2000prf.googlegroups.com... IIRC there were an article a time ago in MSDN magazine about using events in > Hello, > > I am interested in a solution that allows two classes that do not > inherit from Control class and raise events and work togather in async > fashion. a console app. I do remember it was one of the last article in the number. The front page fo the number was related to C# and LINQ. So it will be easy to find. Nad,
In this case, instead of just invoking the delegate, you will want to get the invocation list and then call BeginInvoke on each of the items in the invocation list. This will cause the event to be fired on a thread from the thread pool. Of course, this means that your subscribers have to be aware of the fact that the events they subscribe to are on another thread. Juval Lowy has created an interesting little class called EventsHelper which will do this for you: http://www.idesign.net/idesign/DesktopDefault.aspx?tabindex=-1&tabid=19&download=98 You can find more information about EventsHelper here: http://www.idesign.net/idesign/DesktopDefault.aspx?tabindex=5&tabid=11 -- Show quote- Nicholas Paldino [.NET/C# MVP] - mvp@spam.guard.caspershouse.com <nadeem_***@yahoo.com> wrote in message news:4471a130-48b7-40d4-a9c7-4946bc942997@i12g2000prf.googlegroups.com... > Hello, > > I am working on a c# project using framework 1.1. > Since its a console application,no windows forms are being used. > I am trying to implement event driven classes that just want to raise > the event and continue working( like fire and forget - do not wait for > the event handler in client to finish.) > > I have gone through alot of the articles on internet and MSDN and most > talk about delegates (or BackGroundWorker in 2.0 which I cannot > use.) all the other solutions out there are for classes raisng async > events for windows forms in one way or the other. > > I am interested in a solution that allows two classes that do not > inherit from Control class and raise events and work togather in async > fashion. > > I will really appreciate if some one can help me with this. > > Thanks, > > Nad It's really pretty easy to do. The code below probably won't compile, as I
just wrote it here in the message, but it should be pretty close. As a caviet, you're in for a world of hurt, in terms of needing to go through the concurrency learning curve. As soon as you have multiple threads running at once (which this code does) then concurrency shows up... public event GuidEvent; public void DoingSomething() { string value = Guid.NewGuid().ToString(); Console.WriteLine("It's time to trigger the Async Event"); ThreadPool.QueueUserWorkItem(AsyncGuidEvent, value) Console.WriteLine("Event Triggered. This thread still going..."); } private void AsyncGuidEvent(object o) { // We're on a threadpool thread now. When we raise the event, // the people listening will be called on THIS thread. string s = (string)o; if (this.GuidEvent != null) GuidEvent(s); } -- Show quoteChris Mullins <nadeem_***@yahoo.com> wrote in message news:4471a130-48b7-40d4-a9c7-4946bc942997@i12g2000prf.googlegroups.com... > Hello, > > I am working on a c# project using framework 1.1. > Since its a console application,no windows forms are being used. > I am trying to implement event driven classes that just want to raise > the event and continue working( like fire and forget - do not wait for > the event handler in client to finish.) > > I have gone through alot of the articles on internet and MSDN and most > talk about delegates (or BackGroundWorker in 2.0 which I cannot > use.) all the other solutions out there are for classes raisng async > events for windows forms in one way or the other. > > I am interested in a solution that allows two classes that do not > inherit from Control class and raise events and work togather in async > fashion. > > I will really appreciate if some one can help me with this. > > Thanks, > > Nad
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"Chris Mullins [MVP - C#]" <cmull***@yahoo.com> wrote in message For shame, Chris! You're a concurrency expert.news:%23kDqmjeMIHA.5224@TK2MSFTNGP02.phx.gbl... > It's really pretty easy to do. The code below probably won't compile, as I > just wrote it here in the message, but it should be pretty close. > > As a caviet, you're in for a world of hurt, in terms of needing to go > through the concurrency learning curve. As soon as you have multiple > threads running at once (which this code does) then concurrency shows > up... > > public event GuidEvent; > > public void DoingSomething() > { > string value = Guid.NewGuid().ToString(); > Console.WriteLine("It's time to trigger the Async Event"); > > ThreadPool.QueueUserWorkItem(AsyncGuidEvent, value) > > Console.WriteLine("Event Triggered. This thread still going..."); > } > > private void AsyncGuidEvent(object o) > { > // We're on a threadpool thread now. When we raise the event, > // the people listening will be called on THIS thread. > string s = (string)o; > if (this.GuidEvent != null) > GuidEvent(s); var localGuidEvent = this.GuidEvent; if (localGuidEvent != null) localGuidEvent(s); Otherwise you must be prepared to catch a NullReferenceException if GuidEvent is changed during the execution of AsyncGuidEvent. But then, that's the world of hurt mentioned at the beginning of your reply.... Show quote > } > > -- > Chris Mullins > > <nadeem_***@yahoo.com> wrote in message > news:4471a130-48b7-40d4-a9c7-4946bc942997@i12g2000prf.googlegroups.com... >> Hello, >> >> I am working on a c# project using framework 1.1. >> Since its a console application,no windows forms are being used. >> I am trying to implement event driven classes that just want to raise >> the event and continue working( like fire and forget - do not wait for >> the event handler in client to finish.) >> >> I have gone through alot of the articles on internet and MSDN and most >> talk about delegates (or BackGroundWorker in 2.0 which I cannot >> use.) all the other solutions out there are for classes raisng async >> events for windows forms in one way or the other. >> >> I am interested in a solution that allows two classes that do not >> inherit from Control class and raise events and work togather in async >> fashion. >> >> I will really appreciate if some one can help me with this. >> >> Thanks, >> >> Nad > >
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"Ben Voigt [C++ MVP]" <rbv@nospam.nospam> wrote You're right, of course. That's what i get for posting when I'm tired...> "Chris Mullins [MVP - C#]" <cmull***@yahoo.com> wrote in message >> // We're on a threadpool thread now. When we raise the event, >> // the people listening will be called on THIS thread. >> string s = (string)o; >> if (this.GuidEvent != null) >> GuidEvent(s); > For shame, Chris! You're a concurrency expert. > > var localGuidEvent = this.GuidEvent; > if (localGuidEvent != null) > localGuidEvent(s); > > Otherwise you must be prepared to catch a NullReferenceException if > GuidEvent is changed during the execution of AsyncGuidEvent. But then, > that's the world of hurt mentioned at the beginning of your reply.... -- Chris Mullins
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On Nov 29, 6:20 am, "Chris Mullins [MVP - C#]" <cmull***@yahoo.com> thanks guys for your help.wrote: > "Ben Voigt [C++ MVP]" <r...@nospam.nospam> wrote > > > "Chris Mullins [MVP - C#]" <cmull***@yahoo.com> wrote in message > >> // We're on a threadpool thread now. When weraisethe event, > >> // the people listening will be called on THIS thread. > >> string s = (string)o; > >> if (this.GuidEvent != null) > >> GuidEvent(s); > > For shame, Chris! You're a concurrency expert. > > > var localGuidEvent = this.GuidEvent; > > if (localGuidEvent != null) > > localGuidEvent(s); > > > Otherwise you must be prepared to catch a NullReferenceException if > > GuidEvent is changed during the execution of AsyncGuidEvent. But then, > > that's the world of hurt mentioned at the beginning of your reply.... > > You're right, of course. That's what i get for posting when I'm tired... > > -- > Chris Mullins Are there any good examples that I can try out? The link that Nicholas gave is not working. the other one is for downloading. Also will appreciate if you can guide me to some good articles on this topic. Thanks, Nad.  |
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