Difference Between Timer And Thread?
May 11, 2010I used Timer in VB. then, I want to convert a program with VB.net. So, I used Thread instead of Timer. Then, I am curious what difference they are?
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Synchronize The Timer Event So That The Timer Executes From The Background Worker Thread?
Apr 23, 2009I 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?
Timer In A Thread - Routine Which Is Controlled By A Timer
Aug 13, 2010I 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!
View 18 RepliesVS 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???
View 4 RepliesDifference Between Timer Class And Object?
Nov 25, 2010I'm using vb10. I need to use a timer for forms to turn off and on and I was going to use a timer control and I noticed there is a timer class. What is the difference? Should I use the timer class instead?
View 5 RepliesC# - Difference Between BackgroundWorker And System.Threading.Thread
Oct 24, 2009What is the difference between creating a thead using BackgroundWorker and creating a thread using System.Threading.Thread?
View 2 RepliesRun Timer On Separate Thread
Jun 2, 2012I just finished up my space invaders movement and with all the other timers running it really bogs it down. So I think the best solution would be to make the timers run on separate threads. I know roughly how to do this from a old example I read a long time ago. So I just need a simple sample code to refresh my memory please. Maybe something with message boxes or something to demonstrate the process.
View 1 RepliesHow To Make A Timer To Work On Another Thread?
Aug 19, 2009i have a timer and i want its calculation will be done on another thread, since the timer tick event start whenever its enable property is set to true i don't see how to force it to work in another thread.
View 6 RepliesInconsistant Thread Sleep Timer?
Apr 5, 2011Ok so I have been playing with VB.net and brainstorming ways to accomplish launching a thread reliably every 60 seconds reguardless of how long the prior thread took to do it's work. Here is my question. Given the following code:
[Code]...
My assumption for this output would be that the time between each line would have to be exactly 5000 milliseconds plus the time it takes to execute the rest of the loop which could vary given that there could be an unknown delay due to disk IO. My problem is that looking at lines 10 and 11 and subtracting gives me a difference of 4,958 milliseconds. So my question is what the heck is going on there? How is it possible to get a difference of less than 5000 milliseconds when I have told the thread to sleep for 5000 milliseconds before completing the process. What am I missing?
Timer Within Thread Within Windows Service
Dec 6, 2011Right now I have a windows service which only task is to gather data from a database with a specific DSN and then send out an email if the data is valid. The service contains a timer which ticks every 5 minuts and performs the tasks above.Now I need to re-write the windows service to be able to run on more than 1 DSN.I was thinking of making several threads inside the windows service and then again have a seperat timer inside each thread.Is this a good idea and how can this be done? I want to avoid having a windows service for each DSN.[code]
View 4 RepliesUsing A Timer To Delay Main Thread?
Feb 3, 2011is the first time I tried to use a timer - can't understand why it doesn't work!I need to suspend the main thread for a preset time 'delaymSecs' then let the thread continue.I tried this code fragment:-
System.Timers
'(etc)
Public
[code].....
Create A Timer To Execute On A Separate Thread?
Jan 23, 2012Currently I'm creating a task that runs a hardware i/o loop for the duration of my program.i.e. it's a task that's created at the program's start and runs a loop that is only broken at the programs termination. Each loop cycle communicates via ethernet to hardware.depending on time outs each cycle takes 30-300 msec)I've noticed that if the loop runs with out any break that the program really slows down... to counter act that I placed a thread.sleep(x) in the loop
View 6 RepliesVS 2010 Timer Event Not Firing In Background Thread?
Nov 6, 2011When I run the following code in the UI thread, it works without issue.
VB.NET private timer as new timer public sub test()timer.enabled = true timer.interval = 1000 timer.start()addhandler timer.tick, addressof timer_tickend sub private sub timer_tick(...) messagebox.show("fff")end sub
But if I run it within a background thread, nothing happens.
VS 2008 Start Timer On A Separate Thread, So It Doesn't Block The UI?
Sep 17, 2009Is it possible to start a timer on a separate thread so it doesn't block the user interface, or do I have to make a thread that I call from the timer?
View 2 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
VS 2008 Difference Of Sleep Function And Pause Function (using Timer) Between A Loop
Aug 20, 2009Hi. what is the difference of sleep function and pause function (using timer) between a loop.
View 12 RepliesVS 2010 Error - Cross-Thread Operation Not Valid: Control TbPlaca1 Accessed From A Thread Other Than The Thread It Was Created On
Aug 13, 2010In one application, I need use 4 simultaneous threads.When the threads finished, I need to update the text of a TextBox.So, I create 4 Textbox, and I wanna the threads change the text to FINISHED.Each thread change one distinct TB.I use this "example"
Dim Terminados As Integer = 0
Private Sub frmEnviarMensagem_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Timer1.Enabled = True
Timer1.Start()
[code]....
The problem is, I have an error in the red lines.The error is: INVALIDOPERATIONEXCEPTION "Cross-Thread operation not valid: Control tbPlaca1 Accessed from a thread other than the thread it was created on."I don't use cross threading. Each TB only was accessed for the correspondent thread, and for the "main program".
Cross-thread Operation Not Valid: Control 'Panel1' Accessed From A Thread Other Than The Thread It Was Created On." ?
Nov 3, 2011This is the error message I am getting:
"Cross-thread operation not valid: Control 'Panel1' accessed from a thread other than the thread it was created on." The reason I am getting this error is because I am opening up a new form and then calling these three things:
Panel1.Show()
Label1.Show()
Label2.Show()
why I get this error message because it doesn't occur normally if I open Form2 after closing Form1, it only occurs when I open Form2 after closing Form4.
Error - Cross-thread Operation Not Valid: Control 'txt1' Accessed From A Thread Other Than The Thread It Was Created On
Jul 21, 2009I have done a program using vb2005 to display reading from my microcontroller bs2 board but have encountered some problems. My code are as follows.
Dim Stop_Rx As Boolean
Private Sub btnRead_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRead.Click
SerialPort1.Open()
[code]....
I've encounter an error which is, (Cross-thread operation not valid: Control 'txt1' accessed from a thread other than the thread it was created on.)
Error : Cross-thread Operation Not Valid: Control 'l_users' Accessed From A Thread Other Than The Thread It Was Created On
Jun 21, 2012When my client try to connect to server I'm getting this error : Cross-thread operation not valid: Control 'l_users' accessed from a thread other than the thread it was created on.
Private Sub _socketManager_onConnectionAccept(ByVal SocketID As String) Handles _socketManager.onConnectionAccept
l_Users.Items.Add(SocketID)
End Sub
Threading Progress Bar In .net - Thread Operation Not Valid Control 'ProgressBar1' Accessed From A Thread Other Than The Thread It Was Created On
Feb 17, 2012Would anyone be able to help me here please. I'm fairly new to VB.net and threading so im just trying to figure out what is happening.When I debug this I am getting the error thread operation not valid: Control 'ProgressBar1' accessed from a thread other than the thread it was created on.
I'm a little lost as to why the error is occuring or how to fix it. I've had to put the progress bar in a separate thread otherwise the GUI crashes
[Code]...
Waiting For Threads - Thread.join Suspend Execution Of Code On Calling Thread Until Spawned Thread Finishes Or Is Aborted
Sep 2, 2010My understanding is that thread.join will suspend the execution of code on the calling thread until the spawned thread finishes or is aborted...
With that in mind, I tried this:
For i = 1 to 50
threads = New Thread(AddressOf test)
threads.IsBackground = True
threads.SetApartmentState(ApartmentState.STA)
[CODE]...
However, the rest of the code runs when the loop finishes, not waiting for all the spawned threads to finish. Since the rest of the code needs the threads to finish (otherwise the rest will error).
Cross-thread Operation Not Valid: Control 'Autocad' Accessed From A Thread Other Than The Thread It Was Created On
Jun 6, 2010I have written an application that loads a form - frmCad as well as AutoCad. It does this via a class which detects when AutoCad quits.
Friend Class CadApp Private WithEvents AppObject As AcadApplication... Private Sub AppObject_BeginQuit(ByRef Cancel As Boolean) Handles AppObject.BeginQuit RaiseEvent Quit() End SubEnd Class
My main class loads frmCad as well as CadApp.
Public Class Cad Private WithEvents frmCad As CadForm Private WithEvents app As CadApp... Public Sub ShowForm() If frmCad Is Nothing Then frmCad = New CadForm frmCad.Visible = True End Sub... Private Sub app_Quit() Handles app.Quit frmCad.Dispose() frmCad = Nothing .... End Sub
When I debug the program, it stops at frmCad.Dispose()The program continues to execute, but all the code after it fails to work.Looking more carefully I get an error message which contains:-Cross-thread operation not valid: Control 'Autocad' accessed from a thread other than the thread it was created on.
Cross-thread Operation Not Valid: Control 'label2' Accessed From A Thread Other Than The Thread It Was Created On?
Feb 9, 2011My error:Cross-thread operation not valid: Control 'label2' accessed from a thread other than the thread it was created on. I want to be able to give my Public RunBot() sub access to edit Labels, buttons, etc without an error.
[Code]...
Cross-thread Operation Not Valid: Control 'lblStatus' Accessed From A Thread Other Than The Thread It Was Created On
Apr 1, 2010I'm getting the 'System.InvalidOperationException' error on acccessing a thread from other than where it was created. My code is:
'Required by the Windows Form Designer
Public components As System.ComponentModel.IContainer ' changed from private
[code]....
Cross-thread Operation Not Valid: Control 'statusHO' Accessed From A Thread Other Than The Thread It Was Created On
Jun 6, 2009My problem is Cross-thread operation not valid: Control 'statusHO' accessed from a thread other than the thread it was created on.
System.InvalidOperationException was unhandled
Message="Cross-thread operation not valid: Control 'statusHO' accessed from a thread other than the thread it was created on."
Source="System.Windows.Forms"
StackTrace:
[Code]...
i used it and it works fine then. but as it is mentioned its not a good practice to use it. So what should i do? is it ok if i use this as i am not able to use correct practice. Mine application is not for enterprise purpose. its just my class project, and it works fine even if i put application working in background. System works ok. I dont know how to correct this error.As i dont have that much knowlege of threads.
So please guide me how to fix this in correct way otherwise i am force to go for bad programming practice
Please refer to Windows Mobile Developer Center > Smart Device Development Forums > Windows Mobile Development > Appendtext not working for all my code details
Cross-thread Operation Not Valid: Control 'lv1' Accessed From A Thread Other Than The Thread It Was Created On?
Aug 4, 2009Cross-thread operation not valid: Control 'lv1' accessed from a thread other than the thread it was created on.
Dim lvi As ListViewItem
For Each lvi In lv1.Items
[code]....
Error Saying "Cross-thread Operation Not Valid: Control 'lblOnline' Accessed From A Thread Other Than The Thread It Was Created On."?
Feb 7, 2011Ok i have a Form with the following
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
txtNotepad.Text = LoadFile("notes.txt")
[code].....
Extend My Interval Timer Timer To Include Hours In Addition To Minutes And Seconds?
Aug 2, 2010What I need to do to make this code work for hours as well?[code]...
View 6 Replies.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.