C#

delegate object WorkDelegate(string arg);
public object DoWork(string arg)
{        
    WorkDelegate d = new WorkDelegate(DoWorkHandler);
    IAsyncResult res = d.BeginInvoke(arg,null,null);
    if(res.IsCompleted == false)
    {
        res.AsyncWaitHandle.WaitOne(10000,false);
        if(res.IsCompleted == false)
            throw new ApplicationException("Timeout");
    }
    return d.EndInvoke((AsyncResult)res);
}
private object DoWorkHandler(string arg)
{
    Thread.Sleep(5000);
    return "blah " + arg;
}