Can Timer Trigger An Exception On Firing
Aug 8, 2010
I am looking to create a 500ms timer that I can use to make some text flash.Setting up the timer is straight forward enough, but I have not found an example of letting the timer create an exception so I do not have to poll it for a timeout.
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Feb 12, 2010
This application is meant to run at all times to download a web page every minute.To avoid freezing the UI, I read that the best solution is to move the code from a While/Sleep loop to a Timer that will be triggered every minute.The problem I have, is that the user must wait for a minute before the event is triggered:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Interval = 60000
Timer1.Enabled = True
[code]....
Is it possible to force this event to occur instead of waiting for it?
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Feb 10, 2011
I used a timer in my user control now when Timer_Tick event is fired I want to raise an event like Ticked. I created:
public delegate sub myDel()
public event myevnt as myDel
in Timer.Tick
I used raiseEvent myevnt. I also raised the event from a button click. This event is handled in a windows form where the control is used, My problem is event is firing when the button is clicked but not firing from the timer.tick. Is there any problem from Timer.Tick.
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May 7, 2008
I 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
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Mar 31, 2011
I have created a windows service and I have two different timer variables in there. 1st one fires off every 5 seconds and then does whats it is required to do. The second one fires every 30 seconds.
I make sure that when the function are getting executed I disable both the timers and enable once the function is complete.My problem is my second longer (30 second ) timer never fires only the first one is firing. I had created this service 3 months ago and it was working fine till now. But now I do not see the timers work properly in a simple windows app i created to test their workings.
[Code]...
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Aug 4, 2011
I am a newbie, but I am unable to get this code working. FileSweeper is supposed to start a timmer that triggers fileCopy on a web server. fileSweeoer is triggered by global.asax.ileCopy then will copy the filWould it make any difference if this was a class running on a web server?
Imports Microsoft.VisualBasic
Imports System
Imports System.Threading
[code].....
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Nov 6, 2011
When 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.
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Feb 4, 2011
I have the following subroutines:
Private Sub Exceptionquery()
Dim connection As System.Data.SqlClient.SqlConnection
Dim connectionString As String = "Initial Catalog=mdr;Data Source=xxxxx;uid=xxxxx;password=xxxxx"
Dim _sql As String = "SELECT [Exceptions].Employeenumber,[Exceptions].exceptiondate,
[Code] .....
And when I press the button:
Public Sub exceptionsButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exceptionsButton.Click
My subroutine Exception query is not being fired. I know that it's probably something simple that I'm overlooking but don't know what it is.
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Jan 25, 2010
I have an ASP.Net form where I use a DropDownList control to display data retrieved from a table. However setting the SelectedValue of the DropDownList to a value not existing in the dropdown list does not trigger an exception.
[Code]....
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Feb 12, 2010
Eg. ""vb.net" timer event trigger on purpose". This application is meant to run at all times to download a web page every minute. To avoid freezing the UI, I read that the best solution is to move the code from a While/Sleep loop to a Timer that will be triggered every minute. The problem I have, is that the user must wait for a minute before the event is triggered:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Interval = 60000
Timer1.Enabled = True
[CODE]...
Is it possible to force this event to occur instead of waiting for it?
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Feb 18, 2012
I have a main form that has a dynamically generated treeview and also a panel control. Depending on the selection made within the treeview the panel docks 1 of three diffrent usercontrols which are full sub forms(done for ease of modifing design of sub form rather than layering panels on top of panels).Upon button click withing usercontrol i wish to trigger event within main form.For example delete button wich then triggers to remove current selected node from treeview. code for 1 of three diffrent user controls
Dim ctrlQ As New QuoteUC(TrViewQuotation.SelectedNode)
PnlSubFormDock1.Controls.Add(ctrlQ)
Code for delete button for which i need to raise event.
If MsgBox("Are you sure you wish to delete this customer ?", vbYesNo, "Delete Record") = vbYes Then
Deletecustomer(n)
End If
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Oct 6, 2011
i have to develop a software for motorola mc9090 that reads barcodes and rfids simultaneously, so i need to catch two different triggers: the one on the keyboard for barcodes and the other in the backside for rfids.the problem is that i didn't find any sample that illustrates how to set the trigger to read only barcodes, i found something on emdk 2.5 samples that shows how to set the trigger to read rfids but nothing for barcodes. So when i press any trigger the barcode reader is always enabled with rfids reader.Does exist a way to manage them with separated triggers?
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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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May 8, 2009
It is possible to catch an exception and throw a new exception which wraps the first exception as an inner exception: [URL] Also, if I call a function and it throws a certain error, but I catch it, will the calling code's catch handler execute? If so, and it is of a higher exception type, is this not wrapping the exception? eg I can throw exception ex of type IndexOutOfRange, log it but rethrow, catch a higher up exception and do something, or I can throw a new exception and wrap an inner exception like:
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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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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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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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Sep 2, 2009
I have a large project where we have 2-3 dll projects that are converted from VB6 to VB.NET. We have fixed all the issues that caused compilation errors, and most of obvious issues in running, so now we have basically a program up and running. The exe is created from scratch in VB.NET, using a lot of functionality from the converted dll's (including GUI forms). What I wonder is when I run the program in debug mode, I get a bunch of warnings in the "Immediate Window" saying:
A first chance exception of type 'System.Exception' occurred in Microsoft.VisualBasic.dll
...and some of other type (but most of them in Microsoft.VisualBasic.dll).I was wondering if this is common in projects converted from VB6, or if it is caused by bad design in our code...
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Jul 2, 2010
When I try to create a instance of a COM class it throws an exception as Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
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Sep 30, 2009
When I try to create a instance of a COM class it throws an exception as Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
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Mar 15, 2009
I already created a button "enjoy button" that i want to move in a form when the "timer start button" is clicked.how do link the timer to the"timer start button" and make it move? this is what i tried so far..then am blank first
Quote:
Private Sub MainForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Me.xTimer.Enabled = False
xTimer.Interval = 10[code].........
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