Timer Class in ASP.NET

Question

I have this code in the asp.net application start evert, and I'm not really familar with the Timer class but what I want to do is have one Trigger that goes off every night at 11 pm, one that goes off at 5:30 in the morning and then every hour after that.

private System.Threading.Timer timer;
protected void Application_Start(object sender, EventArgs e)
{

    int intervalMilliseconds = 60 * 1000; 
    timer = new System.Threading.Timer(new System.Threading.TimerCallback(TimedEvent), null, intervalMilliseconds, intervalMilliseconds);
}
protected void Application_End(object sender, EventArgs e)
{
    if (timer != null) timer.Dispose();
}
private void TimedEvent(object stateInfo)
{
    MyClass.ExecuteCode();

}

*Please no answers in the way of "don't use asp.net to do triggers because of the lifecycle". *Again - please no posts on what not to use. I've received two post both telling me what not to use and both not related to my question which is about the Timer class and how to use it.

Answer 1

When you create your timer and hook up its tick/elapsed event, set the interval to be every 5 minutes or so.

Then in the tick/elapsed event handler, check the current time and perform an action where necessary. Obviously you will also need to record when an actino has been performed so you don't perform it at 10:58 and 11:03 pm.

Answer 2

Have a look at Quartz.NET, which will allow you to set up cron-like triggers.

Answer 3

Maybe a different way of doing what you want: Instead of relying on ASP to be active, perhaps you can just use the windows scheduler to schedule your event. It has more of the scheduling features you want and will be likely be more reliable as well as already debugged. Your timed event can be as simple as accessing http://localhost/YourApp/.aspx. You'll get the same effect with the added benefit that if your app happens to have recycled, your event will still execute as the 1st request.

Answer 4

You can do the kind of thing you're describing by using the inbuilt ASP.NET Cache.Add CacheItemRemovedCallback delegate. It's a bit of a roundabout way of using it, but you can do effective scheduling this way.

There's an article here showing how to do it.

More information on the CacheItemRemovedCallback here.

Edit: I know you said no services, but if you check the server and find you can use Scheduled Tasks, you can use that to run a console app on a specific schedule like some other other answers mention.

Answer 5

From your question i'm assuming you don't have full control over your hosting environment, so will try to avoid the schedule it... etc answers.

Having said that, you still need to be aware of the asp.net lifecycle, and your trigger approach is fraught with dangers.

Do you get enough traffic that the application won't end unexpectedly? Do you know the configuration of IIS, so recycling is not a worry?

I can see three approaches:

I would recommend having a page, which uses some sort of key, which is only known by the caller. Have this page triggered by a watchmouse (See: http://www.watchmouse.com/en/), or scheduled crawler on a pc/server which will always be on, at the times you need it to be triggered.

An alternative would be to trigger a database process, which runs when needed to. Depending on your environment, this can be scheduled too.

Another would be to check a log file, on users accessing the page, and if it is the first access within the hour, trigger your process. (Do this for whatever period you need.)
However this depends entirely on how heavily your site is accessed, and may not work reliably.