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Conversion from VB6 to VB.NET Architectural Questionnow and I would like another person's point of view. This issue involves the conversion of a VB6 app to VB.NET. In this VB6 app, the original programmer used 5 timers to periodically scan a document, process it, and display thumbnail images of the scanned document. These 5 timers implement 5 different subroutines that enable this process. In my conversion of this app to VB.NET, I have investigated and implemented threads, threadpools, timers, and now async delegates with varying degrees of success (in regards to application performance.) What I am trying to do is to try to simulate the original VB6 timers (that implement the 5 different routines) to the new .NET approach as follows: Original New VB6 App VB.NET App ------------------------------------------- Timer 1 Main Threading Timer - (Encapsulates Threadpools 2 thru 5) Timer 2 Threadpool 1 - (Scans document) Timer 3 Threadpool 2 - (Executes another program as a process for image character recognition) Timer 4 Thread pool 3 - Display Thumbnail images Timer 5 Threadpool 4 - Exits after the above Threadpools are done This worked but was so CPU intensive that it did not allow me to implement other features. For example, once the app started running, it was polling the scanner so much that the UI did not allow me select the scanned bitmap images to expand them. When I varied the Threading Timer values, I was able to expand the bitmap images but it was still very slow. I understand that win forms are not thread safe and I did implement the code necessary (ie. invoke required...etc.). I understand that using Async delegates can also do the polling necessary and some have stated that it is "cleaner" than using Timers and Threadpools in this case. Architecturally speaking, what would be the best way to have this converted to VB.NET and still have the same functionality and responsiveness?? What other approach would I use other than what I have described?? Since responsiveness is the key, is using Async delegates a viable option?? Thanks so much in advance! Viet Sorry cant be of much help architecturaly but here are my 2 cents.
Did you consider using one of the many Timers available in .NET just to make sure that your app gets going atleast for the time being. One more thing, u mentioned "when I varied the Threading Timer values", what exactly do you mean by this. I assume your are using Sleep to make the polling wait for a while. HTH rawCoder Show quoteHide quote "Viet" <v***@starcalif.com> wrote in message news:ObZdqmFQFHA.3628@TK2MSFTNGP12.phx.gbl... > I have an architectural issue that I have been working on for quite awhile > now and I would like another person's point of view. This issue involves the > conversion of a VB6 app to VB.NET. > > In this VB6 app, the original programmer used 5 timers to periodically scan > a document, process it, and display thumbnail images of the scanned > document. These 5 timers implement 5 different subroutines that enable this > process. In my conversion of this app to VB.NET, I have investigated and > implemented threads, threadpools, timers, and now async delegates with > varying degrees of success (in regards to application performance.) > > What I am trying to do is to try to simulate the original VB6 timers (that > implement the 5 different routines) to the new .NET approach as follows: > > Original New > VB6 App VB.NET App > ------------------------------------------- > Timer 1 Main Threading Timer - (Encapsulates Threadpools 2 thru 5) > Timer 2 Threadpool 1 - (Scans document) > Timer 3 Threadpool 2 - (Executes another program as a process for > image character recognition) > Timer 4 Thread pool 3 - Display Thumbnail images > Timer 5 Threadpool 4 - Exits after the above Threadpools are done > > This worked but was so CPU intensive that it did not allow me to implement > other features. For example, once the app started running, it was polling > the scanner so much that the UI did not allow me select the scanned bitmap > images to expand them. When I varied the Threading Timer values, I was able > to expand the bitmap images but it was still very slow. I understand that > win forms are not thread safe and I did implement the code necessary (ie. > invoke required...etc.). > > I understand that using Async delegates can also do the polling necessary > and some have stated that it is "cleaner" than using Timers and Threadpools > in this case. Architecturally speaking, what would be the best way to have > this converted to VB.NET and still have the same functionality and > responsiveness?? What other approach would I use other than what I have > described?? Since responsiveness is the key, is using Async delegates a > viable option?? > > > Thanks so much in advance! > Viet > > > > > > > Rawcoder,
Thanks for your reply. I have considered the many Timers available in .NET but the problem that I was having was that once the app started executing with the timer, it was difficult to do other things since the timer was taking a majority of the CPU time (due to all the polling). I considered executing the timer as a different Thread but I still needed to keep the constant scanner polling functionality and hence my problem: how to keep the scanner constantly polling but still keep the app UI responsive to user demands without loss of responsiveness. I know that there has to be a way since alot of apps implement this multitasking feature. In regards to the second paragraph, my original code for the threading timer was as follows: Dim stateTimer As System.Threading.Timer = New System.Threading.Timer(timerDelegate, evt, TimeSpan.FromSeconds(3), TimeSpan.FromSeconds(5)) By changing the values, one can determine how fast or how slow polling can be. The answer is probably something simple that I am overlooking or something that I am implementing incorrectly in current design. Thanks, Viet Show quoteHide quote "rawCoder" <rawCo***@hotmail.com> wrote in message news:uVuQM9GQFHA.1392@TK2MSFTNGP10.phx.gbl... > Sorry cant be of much help architecturaly but here are my 2 cents. > > Did you consider using one of the many Timers available in .NET just to make > sure that your app gets going atleast for the time being. > > One more thing, u mentioned "when I varied the Threading Timer values", what > exactly do you mean by this. I assume your are using Sleep to make the > polling wait for a while. > > HTH > rawCoder > > "Viet" <v***@starcalif.com> wrote in message > news:ObZdqmFQFHA.3628@TK2MSFTNGP12.phx.gbl... > > I have an architectural issue that I have been working on for quite awhile > > now and I would like another person's point of view. This issue involves > the > > conversion of a VB6 app to VB.NET. > > > > In this VB6 app, the original programmer used 5 timers to periodically > scan > > a document, process it, and display thumbnail images of the scanned > > document. These 5 timers implement 5 different subroutines that enable > this > > process. In my conversion of this app to VB.NET, I have investigated and > > implemented threads, threadpools, timers, and now async delegates with > > varying degrees of success (in regards to application performance.) > > > > What I am trying to do is to try to simulate the original VB6 timers (that > > implement the 5 different routines) to the new .NET approach as follows: > > > > Original New > > VB6 App VB.NET App > > ------------------------------------------- > > Timer 1 Main Threading Timer - (Encapsulates Threadpools 2 thru > 5) > > Timer 2 Threadpool 1 - (Scans document) > > Timer 3 Threadpool 2 - (Executes another program as a process > for > > image character recognition) > > Timer 4 Thread pool 3 - Display Thumbnail images > > Timer 5 Threadpool 4 - Exits after the above Threadpools are > done > > > > This worked but was so CPU intensive that it did not allow me to implement > > other features. For example, once the app started running, it was polling > > the scanner so much that the UI did not allow me select the scanned bitmap > > images to expand them. When I varied the Threading Timer values, I was > able > > to expand the bitmap images but it was still very slow. I understand that > > win forms are not thread safe and I did implement the code necessary (ie. > > invoke required...etc.). > > > > I understand that using Async delegates can also do the polling necessary > > and some have stated that it is "cleaner" than using Timers and > Threadpools > > in this case. Architecturally speaking, what would be the best way to have > > this converted to VB.NET and still have the same functionality and > > responsiveness?? What other approach would I use other than what I have > > described?? Since responsiveness is the key, is using Async delegates a > > viable option?? > > > > > > Thanks so much in advance! > > Viet > > > > > > > > > > > > > > > > 
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