Implement C# Generic Timeout

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 t         


        

Answer 1

Well, you could do things with delegates (BeginInvoke, with a callback setting a flag - and the original code waiting for that flag or timeout) - but the problem is that it is very hard to shut down the running code. For example, killing (or pausing) a thread is dangerous... so I don't think there is an easy way to do this robustly.

I'll post this, but note it is not ideal - it doesn't stop the long-running task, and it doesn't clean up properly on failure.

    static void Main()
    {
        DoWork(OK, 5000);
        DoWork(Nasty, 5000);
    }
    static void OK()
    {
        Thread.Sleep(1000);
    }
    static void Nasty()
    {
        Thread.Sleep(10000);
    }
    static void DoWork(Action action, int timeout)
    {
        ManualResetEvent evt = new ManualResetEvent(false);
        AsyncCallback cb = delegate {evt.Set();};
        IAsyncResult result = action.BeginInvoke(cb, null);
        if (evt.WaitOne(timeout))
        {
            action.EndInvoke(result);
        }
        else
        {
            throw new TimeoutException();
        }
    }
    static T DoWork(Func func, int timeout)
    {
        ManualResetEvent evt = new ManualResetEvent(false);
        AsyncCallback cb = delegate { evt.Set(); };
        IAsyncResult result = func.BeginInvoke(cb, null);
        if (evt.WaitOne(timeout))
        {
            return func.EndInvoke(result);
        }
        else
        {
            throw new TimeoutException();
        }
    }