How do I "pause" a System.Timer in VB.NET?

Question

1.00/5 (2 votes)

See more:

down vote
favorite

I am using a system.timer in a Windows Service to run a process that usually exceeds the timer's interval. I am trying to keep the timer from firing the same code more than once, a known issue with system.timers.

What I want: The timer runs my code, but the timer "pauses" to wait until the code is completed before resuming ticks.

I have two problems:

1. The way system.timers work is that the timer will create a race condition on you by launching new redundant threads of the same code and pile them up on you if the has not completed by the time the timer's interval has elapsed.

2. I would start/stop the timer to keep this from happening, but with a System.Timers.Timer, once you stop the timer for the processing to complete, it never comes back - I have never been able to restart a timer once it has been stopped, it has been destroyed and likely collected. Enabling/disabling is the same exact thing as start/stop with same results.

How on earth do you keep a system.timer from launching new redundant threads of the same code if the process has not completed by the time the timer's interval has lapsed? Obviously, starting/stopping (enabling/disabling) the timer is NOT a solution, as it doesn't work.

Help!

Posted 28-Aug-15 12:34pm

Member 8474866

Updated 21-Feb-17 15:10pm

Add a Solution

Comments

Sergey Alexandrovich Kryukov 28-Aug-15 20:32pm

I don't know such class System.Timer? What timer do you really use? Why using timer at all?
—SA

PIEBALDconsult 28-Aug-15 21:53pm

You can disable it at the beginning of the method and re-enable it at the end.

3 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CoderzF1 · Answer 1 · 2015-08-28T13:31:00

something to try.
its not exactly pausing the timer, just skipping over the code until it gets done executing.

VB

'set a global variable
Public PassOver as Boolean = False

then in the code that the timer fires use the following:

VB

if PassOver = false then
   PassOver = true
   'place code to fire here
   PassOver = False
end if

Patrice T · Answer 2 · 2015-08-28T13:34:00

Solution 2

You can't stop a system timer, never.
all you can do is disable the timer or make your code safe against running more than once.

You need a permanent variable to store the program status.

VB

If Busy Then Return
End If
Busy = True

' do your stuff here

Busy= False

Posted 28-Aug-15 13:34pm

Patrice T

Comments

Sergey Alexandrovich Kryukov 28-Aug-15 20:34pm

Which timer class are you talking about?
—SA

Patrice T 28-Aug-15 21:27pm

For me, a timer is linked to RTC.
With Windows, the word timer is a wrap for something pretty sophisticated.

Neil Tsakatsa · Answer 3 · 2017-02-21T15:10:00

Solution 3

You can try using the System.Threading class.

The code will look something like this :

VB

Sub Test()
     Dim myThread As System.Threading.Thread = Nothing
     Dim myWebBrowser As WebBrowser = Nothing
     myThread.Start(myWebBrowser)

     ' Suspends the current thread for a specified time
     Threading.Thread.Sleep(10000)
 End Sub

Posted 21-Feb-17 15:10pm

Neil Tsakatsa

Comments

Graeme_Grant 21-Feb-17 22:21pm

this is just wrong!

Neil Tsakatsa 12-Apr-17 21:54pm

This guy was talking about pausing the timer. The timer control cannot be paused and by the way, the timer acts as some form of a loop, so instead of using the timer, you can put the code into a thread that can be paused/stopped and then reignited again ! It's correct if you want your code to have some breaks/lapses.

Graeme_Grant 12-Apr-17 22:05pm

You don't apply a kludge fix to an incorrect way of doing things.

You also missed my point totally unlike Ralf. Why answer a 2-year-old tombestoned question??

Neil Tsakatsa 13-Apr-17 4:30am

There are many ways to kill a cat ! If I think I have something to share I have to share it iregardless of whether it's a 2 or 10 year old question. Someone might be having the same problem right now, this guy is not the first one having this problem and probably not the last. That answer will probably help someone maybe 5 years from now ! That's what open source community is for. If you are not a fan of open source, you should probably try Apple !

Graeme_Grant 13-Apr-17 4:39am

You may want to read the website's posting T&Cs...

I look forward to your Open Souce community article contributions then.

Neil Tsakatsa 13-Apr-17 5:58am

Thank You. In an Open Source Environment, anyone can share their opinions.

Ralf Meier 22-Feb-17 1:10am

I agree with Graeme. This code has nothing in common with the original question (from nearly 2 years ago).

How do I "pause" a System.Timer in VB.NET?

3 solutions

Solution 1

Solution 2

Solution 3

Add your solution here

Preview 0

Existing Members

...or Join us