.net - Accurate Windows Timer - System.Timers.Timer() Is Limited To 15 Msec
Jan 15, 2009
I need an accurate timer to interface a Windows application to a piece of lab equipment.I used System.Timers.Timer() to create a timer that ticks every 10 msec, but this clock runs slow. For example 1000 ticks with an interval of 10 msec should take 10 wall-clock seconds, but it actually takes more like 20 wall-clock sec (on my PC). I am guessing this is because System.Timers.Timer() is an interval timer that is reset every time it elapses. Since it will always take some time between when the timer elapses and when it is reset (to another 10msec) the clock will run slow. This probably fine if the interval is large (seconds or minutes) but unacceptable for very short intervals.Is there a function on Windows that will trigger a procedure every time the system clock crosses a 10 msec (or whatever) boundary?
UPDATE: System.Timers.Timer() is extremely inaccurate for small intervals.I wrote a simple program that counted 10 seconds several ways:
Interval=1, Count=10000, Run time = 160 sec, msec per interval=16
Interval=10, Count=1000, Run time = 16 sec, msec per interval=15
Interval=100, Count=100, Run time = 11 sec, msec per interval=110
Interval=1000, Count=10, Run time = 10 sec, msec per interval=1000
It seems like System.Timers.Timer() cannot tick faster that about 15 msec, regardless of the interval setting.Note that none of these tests seemed to use any measurable CPU time, so the limit is not the CPU, just a .net limitation (bug?)For now I think I can live with an inaccurate timer that triggers a routine every 15 msec or so and the routine gets an accurate system time. Kinda strange, but...I also found a shareware product ZylTimer.NET that claims to be a much more accurate .net timer (resolution of 1-2 msec). This may be what I need. If there is one product there are likely others.
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Jun 15, 2009
I'm wondering what exactly is the difference System.Timers.Timer and System.Windows.Forms.Timer???
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Apr 4, 2012
Here is the stack trace:
2012-03-16 19:15:09Z E System.NullReferenceException: Object reference not set to an instance of an object.
at System.Timers.Timer.set_Enabled(Boolean value)
at System.Timers.Timer.Stop()
Here's the code:
Timer declared as private member variable.
Private _myTimer As System.Timers.Timer
Initialize timer method.
[code]....
The timer has to have a value or else the Timer.Stop() call would be throwing the exception. This is a sporadic error and I'm just trying to see if anyone has experienced this before or if anyone has any ideas of what could be causing it. It is occuring in a WinForms application in the event handler for the Elapsed event of the Timer, but it is only occuring sporadically on the users computer. I haven't been able to reproduce the error myself.
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Jun 27, 2012
I'm looking at how to pause a System.Timers.Timer and I cannot figure out the proper way to pause it without resetting the timer.
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Apr 18, 2011
I have a problem with the Timer class in that there is a chance that a timer would fire right before you call Dispose() since you will probably call Dispose() from some other thread. You may have something like:
Public Sub TimerTick() Handles itsTimer.Elapsed
Do Something
End Sub
And then from somewhere else in the code, when your app is done, you call
itsTimer.Dispose()
The only way I can think of doing this is:
Public Sub SomeMethod()
SyncLock(itsTimer.SynchronizingObject)
itsTimer.Dispose()[code]...
This is not a great thing to do esp. since I am holding a lock on an object I am disposing. I can create my own lock and syncLock on that but is there a simple way?
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Oct 18, 2009
is it possible to specify a System.Timers.Timer with 0.1ms interval?
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Mar 8, 2011
I'm creating a multi-threaded application (although it is not at the moment) which will be connecting to a large number of sockets. I've noticed when a connection cannot be made the connect timeout is rather large, so I am trying to make my own. Here is what I have come up with...
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
CreateSockets(2)
AssignSockets(0, "192.168.31.2", 80, False, False) 'shouldn't connect
AssignSockets(1, "192.168.1.1", 80, False, False) 'should connect
[code]....
Looking at the timeoutOccured() sub, you can see I'm unsure of how to specify which index to set. Efficiency is important since this will be housing a lot of connections at once. Something else that just came to mind, would .theTimer.Stop reset the tick value on the timer?
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Feb 2, 2011
There is a problem with standard System.Timers.Timer behaviour. The timer raise Elapsed event with some interval. But when time of execution inside Elapsed event handler exceed timer interval then thread pool begin queuing event handling. This is a problem in my case. This is because with my Elapsed event handler I fetch some data from database and doing something with it and finally save results back to database. But data handling should be provided only once. So, is there a way to prevent from queuing elapse events for System.Timers.Timer.
As illustration for this issue you can consider next test program:
[code]...
2) Second way is about SynchronizingObject, but it is a valuable only for Windows form application or required additional development of code for implementing object that would be implements ISynchronizeInvoke interface. More about this way you can find here
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Mar 24, 2011
I am using timers in a windows service and facing problem that anytime some exception happens ( say i unplug LAN wire from my computer ) service stops running, What i am expecting is that service should keep on running as i am catching generic exception which should catch the exception on one tick event and again work (next tick)when i plug in LAN wire (i am plugging/un plugging ) LAN wire as this service is reading database from LAN so i want to replicate a failover scneario)
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Oct 1, 2010
I have been trying to create a timer program with VB 2010 to the accuraccy of 0.05seconds (If possible, 0.01s)I insert a timer into the form (Timer1, Interval - 50).[code]But when I run the timer for 1min, the recorded time was 48.05 sec.How can I make my timer more accurate? Is there anything i have done wrongly with the code?
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Mar 19, 2012
When I run my app at first its keeps time accurately for the first minute or so there after it starts loosing seconds, and by the end of the day its minutes behind.I've created a class called ServerTimeTimer that has a timers.timer object that elapses every second and adds a second to a dateTime variable, and a property to retrieve the date time.[code]
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Jan 11, 2010
Hello,
I'm writing a windows service and initially tried just using a regular System.Windows.Forms.Timer, but never saw it's tick event get fired in my debugger. From doing some research, it appeared that I needed to use the S ystem.Timers.Timer control instead. In order to make debugging easy, I set my timer interval to a really short value 1000 ms. I'm seeing some rather strange behavior, though. It appears that my timer control is creating multiple threads within my application, or is this just a bug in my debugger? I have an event handler for the Elapsed event like so:
[code]...
When I step through my code like this, it now appears to work as expected. Has anyone else run into this?
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Feb 4, 2012
I have a System.Windows.Forms.Timer named "DialogBoxTimer" set up on a form. When the form loads, it has a command to stop the timer. I have a routine [SPDataRecd(...)] that handles SerialPort1.DataReceived from a serial port (modem). When it is activated by a modem event, I want it to start the timer [DialogBoxTimer.Start()], but it doesn't work.If the timer is running, SPDataRecd can *stop* the timer [DialogBoxTimer.Stop()], but it can't start a stopped timer.
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May 21, 2011
I'm trying to work out a program where you can set up a variable amount of timers (like egg timers). Each timer works independently of the other (you can stop a timer, reset another, and so on, and the rest are not effected).I thought of using a single timer and then creating a custom egg timer class to handle the countdown, store the current time, etc, and use a collection of these classes inside a timer event (at the tick, do a for each to reduce the countdown on the classes by some milliseconds).Then I got to thinking: all of these egg timer classes in the collection with the for each loop may cause some accuracy loss (say, I add 50 egg timers).
Does anyone think the accuracy loss for updating all of the egg timers would be too adverse? Should I try running them on separate threads (have not thought about how yet), or will that make much difference?
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Dec 28, 2010
Imagine that I have a System.Windows.Forms.Timer with 1000 ms interval. If I call Timer.Start() method and after 500 ms I call again Timer.Start() what happens? The second Start call will reset the interval or not? Are there any side effects?
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Feb 24, 2011
In a vb 2010 project, I have 2 win forms: Form1 and Form2.
In the Form1 class there is a server-based timer: when the "elapsed event" fires, then I update the text of a Label1 on the Form2. A very simple code:
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Feb 26, 2009
Alright, so I'm still working on the slot machine. I have three timers all independently going for my three "wheels" of the slot machine.
My issue, is that I'm trying to make a Stop button to stop each timer one at a time, and I'm not understanding why this code isn't working. The logic completely makes sense, and the first "wheel" stops when I click the button, however, it doesnt appear to stop the other two timers.
CODE:
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Aug 2, 2010
What I need to do to make this code work for hours as well?[code]...
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Jul 9, 2009
I have a timer on a page in ASP.NET.
After a certain period of time elapses, I want to disable the timer.
I want to put a static variable in the timers tick event that will track how many seconds have elapsed.
My question is, will this work?
If user X and Y are viewing the page will they both have separate local static variables?
What is the best method of shutting down an ASP.NET timer after a certain elapsed time?
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Apr 23, 2009
I have a windows application that need to process som quite time consuming jobs. In my first try i did all processing under
the form thread. The result was bad response and update of the form due to the heavy jobs.To get around the problem with bad response from the form i created a new class "processing" where i put all the data processing. Then i instanciated a background worker where i in the "doWork" sub created a new instance of "processing".The "processing" class creates a timer from system.timer, and the timer drives the processing.On the Timer event Elapsed the timer starts a new thread from the thread pool.
My problem is now when i want to asynchronously close the background worker (with the corresponding function call what ever it is called ...) there is still a timer thread out there that causes exceptions for me.
1. How can i close my background worker and at the same time have the timer to be stopped?
2. Is there a way to synchronize the timer event so that the timer executes from the background worker thread?
3. Is there a better approach for me to adapt?
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Jan 11, 2011
I want to create an array of timer in vb.net. My problem is that how will i raise the tick event for a particular timer, say mytimer(x).tick and inside the tick event there is also a button, say mybutton(x) which changes location every interval. for example:
public class blah
dim mybuttons(20) as button
dim mytimer(20) as timer
private sub form_load(....) handles me.load
for x as integer = 0 to 20
[Code]...
i dont know what to do next, all i want is to pass the button mybuttons(x) to mytimer(x) tick event, in which their index number are the same. i want to create one timer per button. how to do that? please help me and post example codes. i've researched the net but i cant understand passing variables, addhandlers, etc. i'm just new to programming object oriented.
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Jul 4, 2011
How can I incorporate the timer so once a page loads the timer activates, waits a few seconds then I tell my program what to do next.I tried this code but it didnt work:
Timer1.Interval = 5000
Timer1.Enabled = True
Timer1.Start()
[code]....
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Sep 30, 2010
Everything is nice and dandy on my pc, then I compile, move it to its final destination and I doesn't work! At first I thought it was a OS problem, but both machines has win7, I then thought it was a compilation problem, installed visual studio on the other pc, recompiled still with no luck, then it dawned on me, may it be a problem of 32bit vs 64bit?The piece of code is this:[code]....
By the way is not a problem of mouse_event, is the timer that doesn't work
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Mar 24, 2009
I have a timer in vb.net and it's interval is 1000ms ,. i have placed in it's timer_tick event a code that will print screen the screen and save it to a database.The problem is when i click outside of the form, or loosing the focus of the mouse to the form containing that timer/printscreen, the timer stops. As a result the printscreen also stops.here are it's properties:
generate member = true
interval = 1000
modifiers = friend
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Jul 14, 2011
I recently switched my code from using the windows.forms.timer to the systems.timer.timer and it has resulted in a multithreading error. I'm using the timer to trigger just one event so multithreading shouldn't be an issue. To give more detail I have implemented the timer at follows:
At the top of the class I have: Private Shared timr1sec As System.Timers.Timer
When the program loads (Private Sub Test_load):
timr1sec = New System.Timers.Timer(1000)
AddHandler timr1sec.Elapsed, AddressOf OnTimedEvent
In OnTimedEvent I call several subroutines, and write some data to the screen using a ListView object.VisualExpress throws the multithreading error on the last line of this code, which is in OnTimedEvent
[Code]...
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Aug 13, 2010
I have a routine which is controlled by a timer. It works perfectly. The problem is that now, I need to run this routine several times, so I need to start differents threads so that my program doesn't get hung up. I've been trying to start my timer inside a thread, but it doesn't work!
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Nov 6, 2009
VB6 create object of timer instead of timer control
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Apr 6, 2009
Is it possible to use a timer to delay code? For example:
[code]...
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Nov 4, 2009
I have used system.timers.timer to watch several folders and move files in my windows service. But the timer event stops now and then. I have read that it is better to use system.threading.timer in services.This is my system.timers.timer
Private Timer As New System.Timers.Timer
AddHandler Timer.Elapsed, New System.Timers.ElapsedEventHandler(AddressOf Me.Timer_Elapsed)
Timer.Interval = 4000
Timer.Start()
[code]....
How do this code look like in system.threading.timer?How do i start and stop the timer using threading? That is very important because i stop the timer when it comes to the elapsed event and when the code har run it starts the timer again!
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Oct 27, 2010
In vb6 you used timer for the randomize seed.I noticed vb10 no longer uses it. Does this mean by default it uses the system timer for the seed?
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