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The big Debate on DoEventsI have a program that receives information from the serial port. Occasionally this information requires me to raise an event and update a progressbar telling me how much of the information I have received. My problem lies there. When i update the progressbar, I need to update the display.... progressbar.refresh, nice and simple, however, if the user clicks on the screen at any point whilst receiving information from the serial port, the whole program appears to lock up.... the screen goes white until the information has completed receiveing information on the serial port. I therefore implemented an Application.doevents() after updating the progressbar. This has slowed the whole process down completely. The information I receive takes about 1 minute to receive, however with a DoEvents call it takes twice as long.... this is not acceptable! Does anyone have any idea how to speed this up whilst also keeping the form alive? I can't allow my users to see a (not responding) at the top of the screen and I can't afford to have the time it takes to receive anything double! Please help! Thanks Dave
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On 14 Jun 2006 01:21:14 -0700, "Dave" <davesa***@gmail.com> wrote: From my own experiences thus far, compared to it's use in VB6,>Ok All, > >I have a program that receives information from the serial port. >Occasionally this information requires me to raise an event and update >a progressbar telling me how much of the information I have received. >My problem lies there. When i update the progressbar, I need to update >the display.... progressbar.refresh, nice and simple, however, if the >user clicks on the screen at any point whilst receiving information >from the serial port, the whole program appears to lock up.... the >screen goes white until the information has completed receiveing >information on the serial port. I therefore implemented an >Application.doevents() after updating the progressbar. This has slowed >the whole process down completely. The information I receive takes >about 1 minute to receive, however with a DoEvents call it takes twice >as long.... this is not acceptable! > >Does anyone have any idea how to speed this up whilst also keeping the >form alive? I can't allow my users to see a (not responding) at the >top of the screen and I can't afford to have the time it takes to >receive anything double! > >Please help! > >Thanks > >Dave DoEvents() in Net does not seem to work and I pretend it doesn't even exist. However, the situation you are describing is a classic example of a process that should be running in a separate thread and would be a good place to start if you're not familiar with Threads. Gene Dave,
Add a Threading.thread.sleep(milliseconds) in the loop Cor Show quoteHide quote "Dave" <davesa***@gmail.com> schreef in bericht news:1150273273.773278.48130@y41g2000cwy.googlegroups.com... > Ok All, > > I have a program that receives information from the serial port. > Occasionally this information requires me to raise an event and update > a progressbar telling me how much of the information I have received. > My problem lies there. When i update the progressbar, I need to update > the display.... progressbar.refresh, nice and simple, however, if the > user clicks on the screen at any point whilst receiving information > from the serial port, the whole program appears to lock up.... the > screen goes white until the information has completed receiveing > information on the serial port. I therefore implemented an > Application.doevents() after updating the progressbar. This has slowed > the whole process down completely. The information I receive takes > about 1 minute to receive, however with a DoEvents call it takes twice > as long.... this is not acceptable! > > Does anyone have any idea how to speed this up whilst also keeping the > form alive? I can't allow my users to see a (not responding) at the > top of the screen and I can't afford to have the time it takes to > receive anything double! > > Please help! > > Thanks > > Dave > Causing the UI thread to block by calling Thread.Sleep in the UI thread
will delay processing of the message queue. It really is better to avoid Application.DoEvents and deal with the serial port processing in another thread. Brian Cor Ligthert [MVP] wrote: Show quoteHide quote > Dave, > > Add a > > Threading.thread.sleep(milliseconds) in the loop > > Cor > > "Dave" <davesa***@gmail.com> schreef in bericht > news:1150273273.773278.48130@y41g2000cwy.googlegroups.com... > > Ok All, > > > > I have a program that receives information from the serial port. > > Occasionally this information requires me to raise an event and update > > a progressbar telling me how much of the information I have received. > > My problem lies there. When i update the progressbar, I need to update > > the display.... progressbar.refresh, nice and simple, however, if the > > user clicks on the screen at any point whilst receiving information > > from the serial port, the whole program appears to lock up.... the > > screen goes white until the information has completed receiveing > > information on the serial port. I therefore implemented an > > Application.doevents() after updating the progressbar. This has slowed > > the whole process down completely. The information I receive takes > > about 1 minute to receive, however with a DoEvents call it takes twice > > as long.... this is not acceptable! > > > > Does anyone have any idea how to speed this up whilst also keeping the > > form alive? I can't allow my users to see a (not responding) at the > > top of the screen and I can't afford to have the time it takes to > > receive anything double! > > > > Please help! > > > > Thanks > > > > Dave > > But....
Using System.threading.thread.sleep(xxx) doesnt keep the window alive as far as i can tell... Heres how the overall thing works. I have a c# class which deals with sending, receiving etc. from the serial port. When the serial port receives a certain line ie. "Hello World" an event is raised to my vb.net program. Upon receiving this event I plot a point on a graph and update my progress bar (also through a raiseevent) It can occur that I receive around 10000 of these certain lines in one sitting and therefore the c# event is fired 10000. The problem lies in that while the system is receiving information from the serial port, they must be able to continue doing things, (moving windows, selecting windows etc.) I dont know how i can thread this system when it only responds to events raised in the c# module of serial communications. If i create a thread and tell it to raise the event from the c# code will that then run all the code in the vb stuff in a seperate thread? thanks Dave Dave wrote:
> But.... That's what I'm saying. It will just block the UI thread which> > Using System.threading.thread.sleep(xxx) doesnt keep the window alive > as far as i can tell... > prevents the message pump from dispatching queued messages. That means forms will appear to hang. Show quoteHide quote > Heres how the overall thing works. I have a c# class which deals with The first thing we need to figure out is what thread that event from> sending, receiving etc. from the serial port. When the serial port > receives a certain line ie. "Hello World" an event is raised to my > vb.net program. Upon receiving this event I plot a point on a graph > and update my progress bar (also through a raiseevent) It can occur > that I receive around 10000 of these certain lines in one sitting and > therefore the c# event is fired 10000. > > The problem lies in that while the system is receiving information from > the serial port, they must be able to continue doing things, (moving > windows, selecting windows etc.) I dont know how i can thread this > system when it only responds to events raised in the c# module of > serial communications. If i create a thread and tell it to raise the > event from the c# code will that then run all the code in the vb stuff > in a seperate thread? > the C# class is executing on. Is it the UI thread or something else. If you have access to the C# code you can determine this by seeing if it even uses a separate thread. If you don't have access to the code then there are a couple of ways of testing this. I'll mention just one. In the event handler examine the value of the Form.InvokeRequired property. If true the method is executing on a thread other than the UI thread. If false the method is executing on the UI thread. Show quoteHide quote > thanks > > Dave Brian,
> Causing the UI thread to block by calling Thread.Sleep in the UI thread To process the close button in a window?> will delay processing of the message queue. It really is better to > avoid Application.DoEvents and deal with the serial port processing in > another thread. > If it is about more ports than I agree with you. Cor Show quoteHide quote "Brian Gideon" <briangid***@yahoo.com> schreef in bericht news:1150292232.839141.297690@h76g2000cwa.googlegroups.com... > Causing the UI thread to block by calling Thread.Sleep in the UI thread > will delay processing of the message queue. It really is better to > avoid Application.DoEvents and deal with the serial port processing in > another thread. > > Brian > > Cor Ligthert [MVP] wrote: >> Dave, >> >> Add a >> >> Threading.thread.sleep(milliseconds) in the loop >> >> Cor >> >> "Dave" <davesa***@gmail.com> schreef in bericht >> news:1150273273.773278.48130@y41g2000cwy.googlegroups.com... >> > Ok All, >> > >> > I have a program that receives information from the serial port. >> > Occasionally this information requires me to raise an event and update >> > a progressbar telling me how much of the information I have received. >> > My problem lies there. When i update the progressbar, I need to update >> > the display.... progressbar.refresh, nice and simple, however, if the >> > user clicks on the screen at any point whilst receiving information >> > from the serial port, the whole program appears to lock up.... the >> > screen goes white until the information has completed receiveing >> > information on the serial port. I therefore implemented an >> > Application.doevents() after updating the progressbar. This has slowed >> > the whole process down completely. The information I receive takes >> > about 1 minute to receive, however with a DoEvents call it takes twice >> > as long.... this is not acceptable! >> > >> > Does anyone have any idea how to speed this up whilst also keeping the >> > form alive? I can't allow my users to see a (not responding) at the >> > top of the screen and I can't afford to have the time it takes to >> > receive anything double! >> > >> > Please help! >> > >> > Thanks >> > >> > Dave >> > > That's correct. The WM_CLOSE message that is posted by closing a form
is not any different than the other windows messages. It will remain in the message queue until the UI thread has finished waiting for the Thread.Sleep function to return and subsequently dispatched other messages which arrived first. It's not about more ports. It's about keeping the UI thread running. Brian Cor Ligthert [MVP] wrote: Show quoteHide quote > Brian, > > > Causing the UI thread to block by calling Thread.Sleep in the UI thread > > will delay processing of the message queue. It really is better to > > avoid Application.DoEvents and deal with the serial port processing in > > another thread. > > > > To process the close button in a window? > > If it is about more ports than I agree with you. > > Cor > Hello Dave,
Since, MS does not provide a serial port component in .NET 1.1, which serial port component did you use? Did you borrow a VB6 COM component or did you use a third party control? I have had simillar problems when I used a .NET serial port class() from a third party. I switched to the VB6 COM component and things started to get sorted out by themselves. Hope this helps. Hi,
Are you using a loop to receive data? Perhaps this is not best. You should consider using the DataReceived event (VS2005) or the OnComm event (such as my DesktopSerialIO dll -- free download from my web site), and the call a Delegate proc to update the UI from that event. There can be good reasons for using DoEvents in serial code (and loops can be part of the receive process, in some cases) -- but, IMO, this isn't one of them. Dick -- Richard Grier, MVP Hard & Software Author of Visual Basic Programmer's Guide to Serial Communications, Fourth Edition, ISBN 1-890422-28-2 (391 pages, includes CD-ROM). July 2004, Revised March 2006. See www.hardandsoftware.net for details and contact information. I've written a couple threading programs but I'm not an expert enough to
help on that front. It does seem the logical thing to do. It might not be good form now that we can program threads but perhaps some old fashioned programming would work too. Have you considered using a counter and only calling doevents on every 10 or 20th time you update the progressbar? You know, increment the counter each time the progress bar is run and if the counter modulus 10 or 20 or whatever you pick = 0 then doevents. Better yet make 10 or 20 into a variable and you can adjust responsiveness vs speed on the fly. Dave wrote: Show quoteHide quote > Ok All, > > I have a program that receives information from the serial port. > Occasionally this information requires me to raise an event and update > a progressbar telling me how much of the information I have received. > My problem lies there. When i update the progressbar, I need to update > the display.... progressbar.refresh, nice and simple, however, if the > user clicks on the screen at any point whilst receiving information > from the serial port, the whole program appears to lock up.... the > screen goes white until the information has completed receiveing > information on the serial port. I therefore implemented an > Application.doevents() after updating the progressbar. This has slowed > the whole process down completely. The information I receive takes > about 1 minute to receive, however with a DoEvents call it takes twice > as long.... this is not acceptable! > > Does anyone have any idea how to speed this up whilst also keeping the > form alive? I can't allow my users to see a (not responding) at the > top of the screen and I can't afford to have the time it takes to > receive anything double! > > Please help! > > Thanks > > Dave > 
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