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Hello
I am using serialport to send and receive some data. The problem is that when i use the serialport.Read(buffer, 0, x) method (x being the number of bytes i need to receive) it does not actually wait for the x nr of bytes to be available in the serialport buffer but reads what is available at certain time. I can use the BytesToRead property to wait for the x bytes to be available in the serialport buffer but then i have no way of detecting readTimeout(). I figured i could use a custom timer, but is it the best way (since i would need to start and stop the timer at high speed)?
Any ideas are welcome.
ty
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I have worked with timers, but it is not good practice to use it, as it consumes much of CPU memory and slows down the process . Better go for Threads, where you have Sleep() method which can be used till you receive all data to your serial port and then use Stop() method.
I am not sure this is the Best way. Its just a suggession.  Rashmi.M.K
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Try to look at it differently. Why don't you simply buffer the bytes yourself.
1) Read serial bytes and add them to your buffer
2) if you have the required amount of bytes or more in your buffer, remove the number you expect and process them (leaving those which are not yet processed in the buffer)
3) back to step 1
This is obviously a polling loop. If you have a WinForms user interface, this loop will lock it up. Therefore you would have to run this loop in a separate worker thread. And it might be a good idea, not to let this thread run under full steam. I don't know what timing interval might be sufficient for your application.
Let's just say you want the loop check for new serial bytes once every second, determining a suitable timing value is up to you. You would then have to add the line
Thread.Sleep(1000);
This excludes the thread from getting any processor time for 1000 milliseconds(= one second). This way your application will use the CPU more economically.
Edit: I just saw that someone had the same idea before meA while ago he asked me what he should have printed on my business cards. I said 'Wizard'.
I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
modified on Wednesday, March 10, 2010 7:20 AM
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Would you please send me sample code in c#
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Yes, sure. Meanwhile, would you please get this many-to-many relationship between two database tables, both with composite primary keys to work? With NHibernate of course. My bosses have little understanding for me playing around with serial ports right now.
Seriously, you already had the code for reading from the serial port working. All else you need you will find in the articles here. Search for 'threads' or 'worker threads'. The rest is up to you. Isn't it a bit unlikely that somebody has just the solution to your problem at hand?
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'.
I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
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In the past I've used sort of a two-part technique; the first part is as the previous poster describes:
get all the available data, pass it along, sleep, repeat
The second part receives those bytes/characters and performs the higher-level task of determining whether or not enough data has arrived, breaking it into proper records/messages and passing those up the chain.
The bottom is breaking the task into smaller parts, encapsulation, detail hiding, etc.
P.S. I still remember a football coach chanting, "get it, get rid of it; get it, get rid of it; get it, get rid of it..." 
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Hi,
I have a windows service running whose job is to look for a process and launch if not found.
The statment is : System.Diagnostics.Process.Start(path,username,password,domain).
parameters are :
path : path to the executable i.e....some path/myapp.exe
username : any windows xp limited account.
domain : String.Empty---i dont know what domain name to give
password : somepassword - a secure string
The windows service is running on local system account.
The error i am getting is Access Denied.
Please help me, what am i doing wrong.
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Are your trying to access a file located in the user's home folder (or a subfolder) under Documents And Settings?
Maybe posting some code would help us out...
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In the service the code is:
public void LaunchProcess()
{
string username = "ihtesham";
SecureString passw = new SecureString();
passw.AppendChar('5');
passw.AppendChar('4');
passw.AppendChar('7');
passw.AppendChar('8');
// This would throw exception
System.Diagnostics.Process.Start(@"D:\COEIA Projects\Parental Control System\bin\Debug\PCS.exe", username,
passw, string.Empty);
}
PCS.exe is the output of another winform project in same solution.
I want to start this pcs.exe from my windows service.
Thanks again..
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That's kind of strange.. I've started Processes using an NT Service before and it has worked just fine. What if you try and put the pcs.exe in another location (perhaps VS has issues [for some reasons] here). Copy the pcs.exe file to D:\temp and change the path
@"D:\COEIA Projects\Parental Control System\bin\Debug\PCS.exe"
to
@"D:\temp\pcs.exe".
Does that work?
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If it's a GUI app, you may need to set your service to interact with the desktop. There's a property for it, but I don't remember exactly what it's called. I think you may need to see it in the installer too, but I'm not sure about that.
I've executed commandline apps from a service with no problem, but GUI apps generally require a user to actually be logged on, hence the requirement for enabling interaction with the desktop..45 ACP - because shooting twice is just silly
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"The staggering layers of obscenity in your statement make it a work of art on so many levels." - J. Jystad, 2001
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Actually i resolved that issue...the problem was that both the windows service and the app were using same BLL.dll (windows libarary) in which i had some common code. Since they were in the same solution,thats why it was giving me a problem. I have solved that now.
But the next problem is if i start a process for user A , user B , user C in my service i can see the processes started against there names in the Task Manager.
But when i log in as user A or user B i cannot see my process from Task Manager this means that processes are not running for these users.
The whole architecture is that i have a windows service which will run when the system is on regardless of who ever is logged in. This service should kick a process(win app) for the user who is currently logged in. But i am struggling with starting this win app process for users when i log in as them.
Any help would be much appreciated.
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Instead of doing it that way, why don't you :
0) Write a system tray app that runs when the user logs in
1) Make the systray app communicate with the service that notifies it when the app starts up
2) Let the service communicate with the running instance of the systray app..45 ACP - because shooting twice is just silly
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"The staggering layers of obscenity in your statement make it a work of art on so many levels." - J. Jystad, 2001
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Thanks John for your suggestion. I would definitely give it a go. For the part(0) of your suggestion, is there any windows event of user logging which i can capture in my .NET code. I mean when the user logs in, some event is fired which i can capture.
Thanks in advance 
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John's suggestion is a good one - try it out. The main issue though is to launch a process on the Administrator account (your parental countrol app) when a user log's on the system (a user with ony User right's) because then they're not able to kill that process using the Task Manager.
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I googled "C# user logon event" and found this:
http://technet.microsoft.com/en-us/library/cc721961%28WS.10%29.aspx[^]
You can google too. .45 ACP - because shooting twice is just silly
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"The staggering layers of obscenity in your statement make it a work of art on so many levels." - J. Jystad, 2001
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hi friends & all contributers!!
i am using a pathgradient brush. i am using a loop to add a single ellipse to add to path and filling that ellipse with path gradient brush and resetting the path.. when the points are too many the application slows down..
Is there any way to make this faster??
Thanks in Advance
Samir
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Basically: No.
The only things you can do are
1) Use a solid brush instead. This may bring some improvement as the color for each pixel does not have to be interpolated
or
2) Use less points in your path. You wrote that performance degrades when too many points are used. This sounds like your graphics path has far too many points. How many are we talking about here? 100? 1000? Especially a curved path can be defined with far less points and still look good.A while ago he asked me what he should have printed on my business cards. I said 'Wizard'.
I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
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Are you drawing directly to the screen or to the memory? I have found out that it is a lot quicker to draw to the Image, then draw that image to screen
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Hey guys,i need some help for vehicle recognition system progject, using AForge. i am new in using AForge.
Thanks.
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can you elaborate your question?
Means, from where you want to recognize vehicle?
Is it static image, video or what?
Life's Like a mirror. Smile at it & it smiles back at you.- P Pligrim
So Smile Please
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jokerleo wrote: Hey guys,i need some help for vehicle recognition system progject, using AForge.
Please read point #2 in the guidelines[^]:
Be specific! Don't ask "can someone send me the code to create an application that does 'X'. Pinpoint exactly what it is you need help with.
“Follow your bliss.” – Joseph Campbell
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hmm, sorry bout that, the objective is to identiy different types of vehicles based on certain paremeters like size,etc. Static image.
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It sounds difficult
Beacause Images are not taken from same view and you are using size as parameter so there calibration is not match.
its better if you can give image link
Life's Like a mirror. Smile at it & it smiles back at you.- P Pligrim
So Smile Please
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hmm. alright, but what if the parameter is car plate. is there any ways?
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