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How to create an event that fires at certain time [duplicate]

I have a service written in C# (.NET 1.1) and want it to perform some cleanup actions at midnight every night. I have to keep all code contained within the service, so what's the easiest way to accomplish this? Use of Thread.Sleep() and checking for the time rolling over?

I wouldn't use Thread.Sleep(). Either use a scheduled task (as others have mentioned), or set up a timer inside your service, which fires periodically (every 10 minutes for example) and check if the date changed since the last run:
private Timer _timer;
private DateTime _lastRun = DateTime.Now.AddDays(-1);
protected override void OnStart(string[] args)
{
_timer = new Timer(10 * 60 * 1000); // every 10 minutes
_timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
_timer.Start();
//...
}
private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
// ignore the time, just compare the date
if (_lastRun.Date < DateTime.Now.Date)
{
// stop the timer while we are running the cleanup task
_timer.Stop();
//
// do cleanup stuff
//
_lastRun = DateTime.Now;
_timer.Start();
}
}

Check out Quartz.NET. You can use it within a Windows service. It allows you to run a job based on a configured schedule, and it even supports a simple "cron job" syntax. I've had a lot of success with it.
Here's a quick example of its usage:
// Instantiate the Quartz.NET scheduler
var schedulerFactory = new StdSchedulerFactory();
var scheduler = schedulerFactory.GetScheduler();
// Instantiate the JobDetail object passing in the type of your
// custom job class. Your class merely needs to implement a simple
// interface with a single method called "Execute".
var job = new JobDetail("job1", "group1", typeof(MyJobClass));
// Instantiate a trigger using the basic cron syntax.
// This tells it to run at 1AM every Monday - Friday.
var trigger = new CronTrigger(
"trigger1", "group1", "job1", "group1", "0 0 1 ? * MON-FRI");
// Add the job to the scheduler
scheduler.AddJob(job, true);
scheduler.ScheduleJob(trigger);

A daily task? Sounds like it should just be a scheduled task (control panel) - no need for a service here.

Does it have to be an actual service? Can you just use the built in scheduled tasks in the windows control panel.

The way I accomplish this is with a timer.
Run a server timer, have it check the Hour/Minute every 60 seconds.
If it's the right Hour/Minute, then run your process.
I actually have this abstracted out into a base class I call OnceADayRunner.
Let me clean up the code a bit and I'll post it here.
private void OnceADayRunnerTimer_Elapsed(object sender, ElapsedEventArgs e)
{
using (NDC.Push(GetType().Name))
{
try
{
log.DebugFormat("Checking if it's time to process at: {0}", e.SignalTime);
log.DebugFormat("IsTestMode: {0}", IsTestMode);
if ((e.SignalTime.Minute == MinuteToCheck && e.SignalTime.Hour == HourToCheck) || IsTestMode)
{
log.InfoFormat("Processing at: Hour = {0} - Minute = {1}", e.SignalTime.Hour, e.SignalTime.Minute);
OnceADayTimer.Enabled = false;
OnceADayMethod();
OnceADayTimer.Enabled = true;
IsTestMode = false;
}
else
{
log.DebugFormat("Not correct time at: Hour = {0} - Minute = {1}", e.SignalTime.Hour, e.SignalTime.Minute);
}
}
catch (Exception ex)
{
OnceADayTimer.Enabled = true;
log.Error(ex.ToString());
}
OnceADayTimer.Start();
}
}
The beef of the method is in the e.SignalTime.Minute/Hour check.
There are hooks in there for testing, etc. but this is what your elapsed timer could look like to make it all work.

As others already wrote, a timer is the best option in the scenario you described.
Depending on your exact requirements, checking the current time every minute may not be necessary.
If you do not need to perform the action exactly at midnight, but just within one hour after midnight, you can go for Martin's approach of only checking if the date has changed.
If the reason you want to perform your action at midnight is that you expect a low workload on your computer, better take care: The same assumption is often made by others, and suddenly you have 100 cleanup actions kicking off between 0:00 and 0:01 a.m.
In that case you should consider starting your cleanup at a different time. I usually do those things not at clock hour, but at half hours (1.30 a.m. being my personal preference)

I would suggest that you use a timer, but set it to check every 45 seconds, not minute. Otherwise you can run into situations where with heavy load, the check for a particular minute is missed, because between the time the timer triggers and the time your code runs and checks the current time, you might have missed the target minute.

You can also try the TaskSchedulerLibrary here http://visualstudiogallery.msdn.microsoft.com/a4a4f042-ffd3-42f2-a689-290ec13011f8
Implement the abstract class AbstractScheduledTask and call the ScheduleUtilityFactory.AddScheduleTaskToBatch static method

For those that found the above solutions not working, it's because you may have a this inside your class, which implies an extension method which, as the error message says, only makes sense on a non-generic static class. Your class isn't static. This doesn't seem to be something that makes sense as an extension method, since it's acting on the instance in question, so remove the this.

Try this:
public partial class Service : ServiceBase
{
private Timer timer;
public Service()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
SetTimer();
}
private void SetTimer()
{
if (timer == null)
{
timer = new Timer();
timer.AutoReset = true;
timer.Interval = 60000 * Convert.ToDouble(ConfigurationManager.AppSettings["IntervalMinutes"]);
timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);
timer.Start();
}
}
private void timer_Elapsed(object source, System.Timers.ElapsedEventArgs e)
{
//Do some thing logic here
}
protected override void OnStop()
{
// disposed all service objects
}
}

Executing a Function at a Specific time

I have a timer running in my app which I want to stop and start according to local time.
So I need something like this:
if ( time = 08:00) {StartTimer();}
If ( time = 18:00) {StopTimer();} //This can be done from the timer event itself
Is there a way to do this without using another timer?
I can stop the timer from within the timer event itself, but how will i start it again?

You can set the timer's interval to 14 hours instead of stopping it or keep it running with short interval and checking additional condition (the time of the day) internally.

You can try this:-
1) Create a console app that does what you're looking for.
2) Use the Windows "Scheduled Tasks" functionality to have that console app executed at the time you need it to run
or
You can also look at this example:-
using System;
using System.Threading;
public class TimerExample {
// The method that is executed when the timer expires. Displays
// a message to the console.
private static void TimerHandler(object state) {
Console.WriteLine("{0} : {1}",
DateTime.Now.ToString("HH:mm:ss.ffff"), state);
}
public static void Main() {
// Create a new TimerCallback delegate instance that
// references the static TimerHandler method. TimerHandler
// will be called when the timer expires.
TimerCallback handler = new TimerCallback(TimerHandler);
// Create the state object that is passed to the TimerHandler
// method when it is triggered. In this case a message to display.
string state = "Timer expired.";
Console.WriteLine("{0} : Creating Timer.",
DateTime.Now.ToString("HH:mm:ss.ffff"));
// Create a Timer that fires first after 2 seconds and then every
// second.
using (Timer timer = new Timer(handler, state, 2000, 1000)) {
int period;
// Read the new timer interval from the console until the
// user enters 0 (zero). Invalid values use a default value
// of 0, which will stop the example.
do {
try {
period = Int32.Parse(Console.ReadLine());
} catch {
period = 0;
}
// Change the timer to fire using the new interval starting
// immediately.
if (period > 0) timer.Change(0, period);
} while (period > 0);
}
// Wait to continue.
Console.WriteLine("Main method complete. Press Enter.");
Console.ReadLine();
}
}

You could create a thread that ticks every second.
There you can check if you want to start or stop your timer.
Read the folowing: Threads.
In your thread add something like:
if (CurrentTime == "08:00")
StartTimer();
else if if (CurrentTime == "18:00")
StopTimer();
Thread.Sleep(1000); // Makes the Thread Sleep 1 Second

Since you need at least one timer running always (to detect when it's 8 in the morning) then you could simply have just a single timer that runs all day.
Whenever the timer ticks, check the time. If it isn't between 0800 and 1800 just return without doing anything and wait for the next tick.
You could try increasing the timer interval to a value that gets you to e.g. 17:55 and then decrease it again, but there will not be any measurable performance difference so IMHO this is work for no benefit.

Intensive Stop/Start of a C# Timer

I've created a watchdog timer (using a System.Windows.Forms.Timer), which triggers if a long period of time expires without receiving a small packet of data:
using System.Windows.Forms;
public class Watchdog
{
private Timer Timer;
public void Go()
{
Timer.Start();
}
public void Reset()
{
Timer.Stop();
Timer.Start();
}
private void OnTimerExpired(object State)
{
Timer.Stop();
DoSomething();
}
public Watchdog()
{
Timer = new Timer();
Timer.Tick += new EventHandler(OnTimerExpired);
Timer.Interval = (1000 * Timeout);
}
}
The main code calls Go(), and then calls Reset() each time a packet is received. If the timer expires, OnTimerExpired() is called.
Since that there may be hundreds of packet receptions per second, and since the main job of the application is to respond to such packets, I'm beginning to wonder if resetting the timer isn't too CPU/OS intensive.
Any idea how calling Timer.Stop()/Timer.Start() this way may impact performance (in terms of latency)?

Use a simple timespan or integer variable as a flag. When the timer ticks, it checks against a Stopwatch object to see how much time has elapsed since the flag was last udpated. If it's longer than your timeout value you trigger your watchdog code.
Now, instead of resetting your timer, other code can just use the stopwatch to update your timespan flag value when a new packet comes in.
You should also either set your timer's tick interval to about 1/2 of what you want the actual timeout duration to be, or have code in the event to set your interval so your next tick event is just a few milliseconds after you would timeout if the connection was severed now. Otherwise you could end up waiting almost twice as long as the timeout duration in the situation where your last packet arrived very soon after a tick event.

Another option, by the way, is to just have a Boolean flag that's set whenever a message comes in. The timer event handler checks that flag and alerts if it's not set. So you have:
private bool GotAMessage = false;
void MessageReceived()
{
// happens whenever a message is received
GotAMessage = true;
}
void OnTimerExpired(object state)
{
if (!GotAMessage)
{
// didn't receive a message in time.
}
GotAMessage = false;
}

A simpler option is to call a method on the WatchDog class that updates a common lastPacketReceived value time a packet is received. Then you only need to start a single timer one time in the WatchDog class that ticks once per timeout interval and compares the current time to the lastPacketReceived value:
public static class WatchDog
{
static object locker = new object();
static long lastPacketReceived;
static Stopwatch stopWatch = new Stopwatch();
static long threshold = 5000;
static WatchDog()
{
Timer watchDogTimer = new Timer(1000);
watchDogTimer.Elapsed += new ElapsedEventHandler(watchDogTimer_Elapsed);
watchDogTimer.Start();
stopWatch.Start();
}
static void watchDogTimer_Elapsed(object sender, ElapsedEventArgs e)
{
lock (locker)
{
if ((stopWatch.ElapsedMilliseconds - lastPacketReceived) > threshold)
{
// threshold exceeded
}
}
}
public static void PacketReceived()
{
lock (locker)
{
lastPacketReceived = stopWatch.ElapsedMilliseconds;
}
}
}

Any idea how calling Timer.Stop()/Timer.Start()
This way may impact performance (in terms of latency)?
None
The amount of resources required to do this is unlikely to be measured. Unless you have a performance problem, don't try to solve a performance problem, at the very least use software to profile the software to see if its an actual problem.

How to correctly implement a custom timer in .Net

I have a requirement for a timer that has the following behaviour:
Millisecond accuracy
I want the tick event handler to only be called once the current tick handler has completed (much like the winforms timer)
I want exceptions on the main UI thread not to be swallowed up by the thread timer so this requires Invoke/Send instead of BeginInvoke/Post
I've played around with CreateTimerQueueTimer and had some success but at the same time had problems with code reentrance and/or locks when deleting the timer.
I decided to create my own timer so that I could get a better idea of what is going on under the hood so that I can fix the locking and reentrance problems. My code seems to work fine leading me to believe that I may as well use it. Does it look sound?
I've put in a check if the timer is deleted to make sure that the deletion is complete before the timer can be created again. Does that look ok?
Note: I should say that I call timeBeginPeriod(1) and timeEndPeriod(1) inorder to achieve the millisecond accuracy.
(The following code is converted from vb.net to c#, so apologies for any missed mess-ups}
ETA: I've found a problem with it. If the timer is running at an interval of 1 millisecond, and I call, say, Change(300), it locks up # while (this.DeleteRequest). This
must be because the TimerLoop is in the this.CallbackDelegate.Invoke(null) call.
public class MyTimer : IDisposable
{
private System.Threading.TimerCallback CallbackDelegate;
private bool DeleteRequest;
private System.Threading.Thread MainThread;
public MyTimer(System.Threading.TimerCallback callBack)
{
this.CallbackDelegate = callBack;
}
public void Create(int interval)
{
while (this.DeleteRequest) {
System.Threading.Thread.Sleep(0);
}
if (this.MainThread != null) {
throw new Exception("");
}
this.MainThread = new System.Threading.Thread(TimerLoop);
// Make sure the thread is automatically killed when the app is closed.
this.MainThread.IsBackground = true;
this.MainThread.Start(interval);
}
public void Change(int interval)
{
// A lock required here?
if (!this.IsRunning()) {
throw new Exception("");
}
this.Delete();
this.Create(interval);
}
public void Delete()
{
this.DeleteRequest = true;
}
public bool IsRunning()
{
return (this.MainThread != null) && this.MainThread.IsAlive;
}
private void TimerLoop(object args)
{
int interval = (int)args;
Stopwatch sw = new Stopwatch();
sw.Start();
do {
if (this.DeleteRequest) {
this.MainThread = null;
this.DeleteRequest = false;
return;
}
long t1 = sw.ElapsedMilliseconds;
// I want to wait until the operation completes, so I use Invoke.
this.CallbackDelegate.Invoke(null);
if (this.DeleteRequest) {
this.MainThread = null;
this.DeleteRequest = false;
return;
}
long t2 = sw.ElapsedMilliseconds;
int temp = Convert.ToInt32(Math.Max(interval - (t2 - t1), 0));
sw.Reset();
if (temp > 0) {
System.Threading.Thread.Sleep(temp);
}
sw.Start();
} while (true);
}
// The dispose method calls this.Delete()
}

I would recommend using p/Invoke and using the timers from Win32's Timer Queues:
http://msdn.microsoft.com/en-us/library/ms686796(v=vs.85).aspx
One should be mindful that the managed CLR environment has a lot of non-determinism built into it, garbage collection, for instance. Just because your timer is has a period of 1 millisecond doesn't mean that that is necessarily what happens.
Also, the documentation doesn't mention it, but the callback invoked by the timer must be pinned in memory and not garbage collectable, via a GCHandle or other construct. When a timer (or timers, if you kill off a timer queue), the callback will be executed one last time. Not sure whether that happens by the internal wait expiring, or by signalling the internal event handle.
Execution of DeleteTimerQueueTimer() and DeleteTimerQueueEx() can be made synchronous, so they won't return until all timers have signalled and invoked their last callback, but doing that would be suboptimal.
If you don't pin the callbacks and prevent them from being garbage-collected, things will go swimmingly...most of the time. You'll encounter random exceptions.
Also, the callback should be smart enough to bail out if the timer is being deleted, lest it make reference to something that's already GC'd.

μTimer would be a better example!
You can find it here # https://stackoverflow.com/questions/15725711/obtaining-microsecond-precision-using-net-without-platform-invoke?noredirect=1#comment22341931_15725711
It provides accurate wait times down to 1µs and possibly lower depending on your NIC!
Let me know if you need anything else!

How to add a timer to an app!

I have an app that I would like to update on an interval. I am looking for maybe some type of if statement or try - catch statement. I already have a foreach statement in the same class, but i dont think I can put in there? I would also like to set it up so that the user can change the refresh rate. Any help is appreciated. Thanks
Here is the method that I would like to put the timer in...
private void _UpdatePortStatus(string[] files)
{
foreach (string file in files)
{
PortStatus ps = new PortStatus();
ps.ReadXml(new StreamReader(file));
if (!_dicPortStatus.ContainsKey(ps.General[0].Group))
{
_dicPortStatus.Add(ps.General[0].Group, ps);
}
PortStatus psOrig = _dicPortStatus[ps.General[0].Group];
foreach (PortStatus.PortstatusRow psr in ps.Portstatus.Rows)
{
DataRow[] drs = psOrig.Portstatus.Select("PortNumber = '" + psr.PortNumber + "'");
if (drs.Length == 1)
{
DateTime curDt = DateTime.Parse(drs[0]["LastUpdateDateTimeUTC"].ToString());
DateTime newDt = psr.LastUpdateDateTimeUTC;
if (newDt > curDt)
{
drs[0]["LastUpdateDateTimeUTC"] = newDt;
}
}
else if (drs.Length == 0)
{
psOrig.Portstatus.ImportRow(psr);
}
else
{
throw new Exception("More than one of the same portnumber on PortStatus file: " + file);
}
}
}
}

Look at the System.Timer class. You basically set an interval (eg. 10000 milliseconds) and it will raise an event every time that interval time passes.
To allow the use to change the refresh rate, write a method that receives input from the user and use that to update the TimerInterval. Note that the TimerInterval is in miliseconds, so you may need to convert to that from whatever the user input.
So, from the example, the event will be raised every 10 seconds:
System.Timers.Timer aTimer = new System.Timers.Timer(10000); //10 seconds
// Hook up the Elapsed event for the timer.
aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
aTimer.Enabled = true; // Starts the Timer
// Specify what you want to happen when the Elapsed event is raised
private static void OnTimedEvent(object source, ElapsedEventArgs e)
{
//Perform update
_UpdatePortStatus(files);
}
UPDATE: In response to your posted code, it appears you simply want to call _UpdatePortStatus to update the port status at regular intervals (see the updated example above).
One important point you need to bear in mind though is that the Timer will run on a separate thread, and as such could raise the event again before it has finished running from the last time if it takes more than the interval time to run.

Use System.Timers.Timer, System.Threading.Timer or System.Windows.Forms.Timer ... depending on what exactly it is that you "would like to update on an interval."
See the following articles:
http://www.intellitechture.com/System-Windows-Forms-Timer-vs-System-Threading-Timer-vs-System-Timers-Timer/
http://www.yoda.arachsys.com/csharp/threads/timers.shtml

Your question is somewhat vague as there an many different methods of achieving what you want to do. However in the simplest terms you need to create a System.Threading.Timer that ticks on whatever frequency you define, for example:
private System.Threading.Timer myTimer;
private void StartTimer()
{
myTimer = new System.Threading.Timer(TimerTick, null, 0, 5000);
}
private void TimerTick(object state)
{
Console.WriteLine("Tick");
}
In this example the timer will 'tick' every 5 seconds and perform whatever functionality you code into the TimerTick method. If the user wants to change the frequency then you would destroy the current timer and initialise with the new frequency.
All this said, I must stress that this is the simplest of implementation and may not suit your needs.