Question

I am working with an ASP site which requires a “reminder” email to be sent out every x, y and z minutes. I have attempted to start a timer upon an event (like a button click or page load) but this proved to be unreliable as the timers would be disposed of when the server performed an automatic backup or when the aspx.cs file was updated.

My new idea is to have a timer constantly running (a check is performed on a page load which ensures its running) and, when it elapses, it checks to see if either x, y or z minutes have elapsed. So if y elapses, it needs to send out a “reminder” email and then restart y’s timer.

void ParentTimer_Elapsed(object sender, ElapsedEventArgs e)
{
    foreach(Timer childTimer in ChildTimerList)
    {
        if(childTimer.Enabled == false) // And therefore has elapsed
        {
            sendReminderEmail(childTimer);
            childTimer = checkAndSetCorrectInterval(childTimer);
            childTimer.AutoReset = false;
            childTimer.Enabled = true;
        }
    }
}

The list ChildTimerList would obviously contain x, y and z.

Can anybody forsee me running into any problems with this, or are there any better ways to approach it? My perfect solution would be a timer running costantly which doesn’t need to be started upon an event but I don’t think this is possible with ASP.

Furthermore, where should I initialise my parent timer and childlist variables? In a class within the App_Code folder or, statically, in a code-behind aspx.cs page?

Thanks in advance.

EDIT:

Yes, I do mean ASP.NET… 🙂

Answer 1

I would probably implement this with a simple console application (responsible for sending e-mails) and Task Scheduler in Windows (responsible for running the application on a schedule). Keep it simple. And robust.

Edit: Provided that you are in control of the server – it will probably not be the best solution in a shared hosting environment where you’re only allowed to run web apps.