I would like a piece of code to run when the clock strikes 10:00:00, 11:00:00, etc.
I would also like another piece of code to run 10:00, 10:10, 10:20, 10:30, 10:40, etc.

Is there an event that I can attach a callback function to?

Windows is actually quite accurate in firing timer events at the correct time. Set your interval so the next event occurs at the correct time.

System.Timers.Timer Tmr = new System.Timers.Timer();

System.DateTime NextTime;

int Tmr_Elapsed_Count;

private void Tmr_Elapsed(object sender, System.Timers.ElapsedEventArgs e)

{

Tmr.Stop();

Sub1();

if (Tmr_Elapsed_Count % 10 == 0)

{

Sub2();

}

Tmr_Elapsed_Count += 1;

NextTime = NextTime.Add(new TimeSpan(0, 10, 0));

Tmr.Interval = NextTime.Subtract(System.DateTime.Now).Milliseconds;

Tmr.Start();

}

You'll need to use a timer (set the interval to 60000 which is 1 min) and every minute check to see if it's time to run one of your pieces of code.

Tough!

I was hoping to get events that fired exactly OnTimeChanged().
I mean, I could be unfortunate and check if the time is right at 09:59:58, and first get notified at 10:00:58.

So a reasonable solution would be to constantly monitor the time in a thread, and when the time is right, run the pieces of code?
Here I mean reasonable in terms of system resources and general code practice.

This may or may not be relevant depending on what exactly you are trying to do, but Windows Scheduled Tasks may be ideally suited for the type of thing you are trying to do. Can you factor out the work you are trying to do into a few simple Console applications (you could still use a common class library) and simply run the appropriate applications at the correct time through the Scheduled Tasks?

Windows is actually quite accurate in firing timer events at the correct time. Set your interval so the next event occurs at the correct time.

System.Timers.Timer Tmr = new System.Timers.Timer();

System.DateTime NextTime;

int Tmr_Elapsed_Count;

private void Tmr_Elapsed(object sender, System.Timers.ElapsedEventArgs e)

{

Tmr.Stop();

Sub1();

if (Tmr_Elapsed_Count % 10 == 0)

{

Sub2();

}

Tmr_Elapsed_Count += 1;

NextTime = NextTime.Add(new TimeSpan(0, 10, 0));

Tmr.Interval = NextTime.Subtract(System.DateTime.Now).Milliseconds;

Tmr.Start();

}

Just check the hour and minute and ignore seconds/milliseconds. Windows is pretty accurate down to the second. Also use DateTime.Now.Minute >= TimeToRun.Minute just in case the event happens to be a minute late.