VS 2008 Difference Between System.Timers.Timer And System.Windows.Forms.Timer?
Jun 15, 2009I'm wondering what exactly is the difference System.Timers.Timer and System.Windows.Forms.Timer???
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.net - Accurate Windows Timer - System.Timers.Timer() Is Limited To 15 Msec
Jan 15, 2009I 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.
VS 2008 Specify A System.Timers.Timer With 0.1ms Interval?
Oct 18, 2009is it possible to specify a System.Timers.Timer with 0.1ms interval?
View 14 RepliesC# - What Could Cause System.Timers.Timer.set_Enabled Property To Throw A System.NullReferenceException
Apr 4, 2012Here 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.
.net - Proper Way To Pause A System.Timers.Timer?
Jun 27, 2012I'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.
View 4 RepliesC# - Proper Way To Dispose Of System.Timers.Timer?
Apr 18, 2011I 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?
Using A Regular System.Windows.Forms.Timer?
Jan 11, 2010Hello,
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?
Index System.timers.timer For When Time Has Elapsed?
Mar 8, 2011I'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?
VS 2010 Can't Start System.Windows.Forms.Timer
Feb 4, 2012I 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.
View 6 RepliesC# - Prevent System.Timers.Timer From Queuing For Execution On A Thread Pool?
Feb 2, 2011There 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
C# - What Happens If Call Start() Two Times On Class System.Windows.Forms.Timer
Dec 28, 2010Imagine 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?
View 3 RepliesIDE :: System.Timers.Timer Working When Exception Occurs In Elapsed Event Handler
Mar 24, 2011I 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)
View 3 RepliesTimers.timer Lossing Time When Compared It To System Time
Mar 19, 2012When 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]
View 5 RepliesCannot Import System.Windows.Media.Imaging And System.Windows.Forms Or System.Reflect?
Mar 16, 2009With the following imported namespaces in my project :
Imports System.Windows.Forms
Imports System.Reflection
.. I cannot add..
[code].....
VS 2008 Get System.Threading.Timer To Work
Sep 27, 2011Trying to get System.Threading.Timer to work!! I am converting a small form based application to run as a services, The app just runs an monitors a folder and then when it finds a file to does some work on it. Having changed the form.timer to threading.timmer - The timer stopps working after a while. Below is a simple test services - when you look in to the text file it stops after approx 130 entries
[Code]...
VS 2008 : A First Chance Exception Of Type 'System.InvalidOperationException' Occurred In System.Windows.Forms.dll
Feb 12, 2011A first chance exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll It displays in my Immediate Window when i run my program, I'm using a text reader to read a number of XML files using background worker...most the time it stops so something is wrong but sometimes it works fine.
View 2 RepliesImplicit Conversions From 'System.Windows.Forms.Control' To 'System.Windows.Forms.Webbrowser'
Sep 8, 2010I have the code which checks if there is a selected tab
Private Function GetBrowser() As WebBrowser
If TabControl1.SelectedTab IsNot Nothing Then
For Each c As Control In TabControl1.SelectedTab.Controls
If TypeOf (c) Is WebBrowser Then
Return c
[Code]...
Forms :: Error - An Unhandled Exception Of Type 'System.StackOverflowException' Occurred In System.Windows.Forms.dll
Apr 14, 2011An unhandled exception of type 'System.StackOverflowException' occurred in System.Windows.Forms.dll it also says make sure you do not have infinate loop or infinate recursion il give all code in order that they are executed in Check the chechbox and it disables all irelevent stuff and populates the combobox
Private Sub CheckBox_Spray_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox_Spray.CheckedChanged
If Me.CheckBox_Spray.Checked = True Then
[code]....
Unable To Cast Object Of Type 'System.Windows.Forms.Button' To Type 'System.Windows.Forms.TextBox'
Apr 28, 2009I have a panel with some controls in it (several textboxes, a slider, 2 buttons, and a small groupbox).. When I click a button, I want all of the textboxes within the panel to be readonly... So I have this code: [code] When I run it though, I get the following error:Unable to cast object of type 'System.Windows.Forms.Button' to type 'System.Windows.Forms.TextBox'.If I remove a button, it moves on to give me the same error but for a label..
View 4 RepliesHow To Use System.threading.timer
Nov 4, 2009I 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!
Uses The System Timer For The Seed?
Oct 27, 2010In 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?
View 2 RepliesTimer To Run Off PC/Server System Time?
Aug 2, 2010I have an application that I'm writing that needs to run 3 different Timers. One that will run every 5 minutes, 1 that will run every hour and 1 that has to run once a day sometime after 5:00 P.M. I know that I can seperate the application into 3 seperate applications and use Windows Scheduled Tasks to perform this however I would prefer to have everything in 1 application and just run the different Sub/Functions off of the appropriate Timer. I'm trying also figure out a way to avoid 2 timers firing at the same time.
What i would like to do is tell the 5 minute timer to run say 2 minutes after every 5 minute mark in the our so the first one would be at 12:07 and then the next would be at 12:12 and so on. The hour timer should run sa at 12:20. The daily one run at say 5:31.Is it possible to use the System.timer or the System.Threading.timer in this way?
Value Of Type 'System.Windows.Forms.WebBrowser' Cannot Be Converted To 'System.Window
Jan 23, 2010Private Sub wb_Scrape(ByVal sender As System.Object, ByVal e As
[Code]...
'System.AccessViolationException' Occurred In System.Windows.Forms.dll Immediately Before Entering A Click Handler?
Oct 20, 2010Win7 64 bit; fully patched VS2008 targeting FW2.0; VB.Net; running in Debug Mode (not tested in Release mode)I have a resonably complex app which I am refactoring a bit. As part of that, I relocated some code from a subroutine into a Click Event Handler. The Event Handler will, late in the handler, call the, reduced in function, subroutine. The point of this is thatNow when I click the button associated with the modified Handler I get:A first chance exception of type 'System.AccessViolationException' occurred in System.Windows.Forms.dll<br />With Error System.AccessViolationException Attempted to read or write protected memory.This is often an indication that other memory is corrupt.
at MusicManager2009.frmMain2.cmdLoadAlbum_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
[code].....
All functions of the app, except those that start from the buttonclick in question, work as before in the problem version.The problem persists after rebuilding the entire solution, after restarting VS, and after rebooting the PC.
Error - An Unhandled Exception Of Type 'System.StackOverflowException' Occurred In System.Windows.Forms.dll
Feb 19, 2010When I run my project I get "An unhandled exception of type 'System.StackOverflowException' occurred in System.Windows.Forms.dll"
Public Class frmViewReport
Dim objForm As New frmViewReport
Private Sub frmViewReport_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
objForm.ViewReport("C:a2.rtp", , "@parameter1=test�mter2=10")
[code]....
Error : A First Chance Exception Of Type 'System.ArgumentException' Occurred In System.Windows.Forms.dll
Nov 16, 2009I have the following code running, the first time I change the selected index, everything runs smoothly. However, if I try to change the selected index again, nothing happens and the subcategories combobox values do not change.
Private Sub cboMainCategory_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboMainCategory.SelectedIndexChanged
'* make sure the combobox is fully loaded
[code]....
Error : An Unhandled Exception Of Type 'System.ArgumentOutOfRangeException' Occurred In System.windows.forms.dll
May 6, 2009I keep getting an eroor this error says: An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in system.windows.forms.dll Additional information: Specified argument was out of the range of valid values.
Option Strict On
Public Class frmWeeklyReport
Inherits System.Windows.Forms.Form
[code].....
Adding Item To A Listbox From A System.Timer
Oct 1, 2009For the last couple of days I been trying to add items to a listbox from another class within a system.timer.
They just don't appear in the listbox. I don't get any errors. The items just don't get added :S.
I have:
Form.vb
make object of Control
Control.vb
Here I have a system.timer
In the Timer_Elapsed method I do this: form.listbox1.items.add("hello")
But it just doesn't work... When I add a new item to the listbox1 from the constructor or another method that has nothing to do with the timer it works...
IDE :: Window Service -System Timer Not Firing?
May 7, 2008I have a Windows Service -which contains a System.Timer -which get enabled and started in the OnStart event handler.In the Timer Elapsed event -I make a call to a routine within another DLL. The problem is that the Timer Elapsed event never fires... I have a test application -which works fine. This is written in VB.Net 2008 framework 3.5
View 3 RepliesSystem Timer - Checking Message Status?
Jun 9, 2010I have application that use MSSQL database. Application have module that is using for sending messages between application users. When one user send message to another I insert message in database, and set message status to 1( after user read message database I update and set message status to 0). Now, I am using system.timers.timer for checking message status, and if message status 1 user get alert that he has one message inbox. The problem is that this application can be used by many users, and if timer run ever 5 minutes this gone slow application and database.
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