Question

I am looking for good ideas for implementing a generic way to have a single line (or anonymous delegate) of code execute with a timeout.

TemperamentalClass tc = new TemperamentalClass(); tc.DoSomething();  // normally runs in 30 sec.  Want to error at 1 min 

I’m looking for a solution that can elegantly be implemented in many places where my code interacts with temperamental code (that I can’t change).

In addition, I would like to have the offending ‘timed out’ code stopped from executing further if possible.

Answer 1

The really tricky part here was killing the long running task through passing the executor thread from the Action back to a place where it could be aborted. I accomplished this with the use of a wrapped delegate that passes out the thread to kill into a local variable in the method that created the lambda.

I submit this example, for your enjoyment. The method you are really interested in is CallWithTimeout. This will cancel the long running thread by aborting it, and swallowing the ThreadAbortException:

Usage:

class Program {      static void Main(string[] args)     {         //try the five second method with a 6 second timeout         CallWithTimeout(FiveSecondMethod, 6000);          //try the five second method with a 4 second timeout         //this will throw a timeout exception         CallWithTimeout(FiveSecondMethod, 4000);     }      static void FiveSecondMethod()     {         Thread.Sleep(5000);     } 

The static method doing the work:

    static void CallWithTimeout(Action action, int timeoutMilliseconds)     {         Thread threadToKill = null;         Action wrappedAction = () =>         {             threadToKill = Thread.CurrentThread;             try             {                 action();             }             catch(ThreadAbortException ex){                Thread.ResetAbort();// cancel hard aborting, lets to finish it nicely.             }         };          IAsyncResult result = wrappedAction.BeginInvoke(null, null);         if (result.AsyncWaitHandle.WaitOne(timeoutMilliseconds))         {             wrappedAction.EndInvoke(result);         }         else         {             threadToKill.Abort();             throw new TimeoutException();         }     }  }