How can I schedule Debugs?

there is this check-in-out program here at my workplace, it only takes the data from check-in-out machine and store it in our database, but suddenly out of nowhere started to report an error on Thursdays but only once at a random time during the day, so when I开发者_开发百科 detect the error, I run the program but nothing happens, so I want to debug it every 5-10 mins to see if I catch the error to see what is happening, how can I do this?

Logging is your friend. Add lots of logging (either use the built-in Trace logging or use some framework such as log4net). Use the different log levels to control how much logging you get out. At verbose levels you can for instance log when you enter and exit important methods, log the input arguments and return values. Log in catch blocks and so on. Then analyse the log files after the next error is reported.

What kind of error logging are you currently implementing in this application? If none, would you consider adding in comprehensive application logging, such as the Log4Net tool? Or if this is a web application the ELMAH tool?

This way you can log every error that happens along with its details, like stack trace to track down the problem.

Some thoughts:

Check the server event log to see if there are any crash minidumps you can pull out. These can tell you a lot about what happened when the program crashed (call stack, etc).

Or write a wrapper program that can run your program and detect when it fails, then take a snapshot of the server's state at that moment so you can (hopefully) re-execute the task with the necessary data to get a repeatable crash in your debugger.

Or just add loads of logging. You could use PostSharp to add trace that tells you every method that you enter and exit, so you can easily determine which method was running when it failed.

And you can add robustification code. Check religiously for nulls, etc. and you may well find you've corrected the problem without necessarily knowing which fix fixed it.

And if the program's not too big, just being old fashioned and desk checking (reading a print-out of) the code may well turn up some bugs.

Another approach (getting a bit more experimental) might be to modify the program to run continuously so you can stick it in a debugger and leave it till you hit an exception. (run a loop, wait for a trigger file to be refreshed or something, and then kick off the normal process - about 5 lines of code would probably suffice)