Historically, debugging windows services can be a minor pain. One either has to either emulate the service controller behavior using a separate console application project or install the service, start it, set a break point and attach the debugger.

Mimicking a console application

Listing 1: ServiceBase extension method

        /// <summary>
        /// Runs the service.
        /// </summary>
        /// <param name="serviceBase">The service base.</param>
        /// <param name="args">The args.</param>
        public static void RunService(this ServiceBase serviceBase, string[] args)
        {
            if (Debugger.IsAttached)
            {
                using (var autoResetEvent = new AutoResetEvent(false))
                {
                    const BindingFlags flags = BindingFlags.NonPublic | BindingFlags.InvokeMethod | BindingFlags.IgnoreCase |
                                               BindingFlags.Instance;

                    var methodInfo = serviceBase.GetType().GetMethod("OnStart", flags);
                    if (methodInfo != null)
                        methodInfo.Invoke(serviceBase, new object[] { args });

                    autoResetEvent.WaitOne();
                }
            }
            else
            {
                ServiceBase.Run(new[] { serviceBase });
            }
        }

Pretty simple stuff…check that the debugger is attached…use reflection to invoke the protected ‘OnStart’ method and block the main thread infinitely with an ‘AutoResetEvent'; otherwise, run the service as normal. Here’s the usage:

    internal static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        private static void Main()
        {
//            ServiceBase[] ServicesToRun;
//            ServicesToRun = new ServiceBase[] 
//            { 
//                new Service1() 
//            };
//            ServiceBase.Run(ServicesToRun);

            new Service1().RunService(null);
        }
    }

Listing 3: Key service controller event handlers

private void OnServiceTimerElapsed(object sender, ElapsedEventArgs e)
        {
            _serviceTimer.Stop();

            var dateTime = DateTime.Now;
            Debug.WriteLine(string.Format("Timer elapsed at {0} {1}...", dateTime.ToShortDateString(), dateTime.ToLongTimeString()));

            _serviceTimer.Start();
        }

        protected override void OnStart(string[] args)
        {
            _serviceTimer.AutoReset = true;
            _serviceTimer.Enabled = true;
            _serviceTimer.Start();

            Debug.WriteLine("Service started...");
        }

To see this in action hit F5 or run the service project instance and you can see that the service is running based on the timer elapsed event in Listing 3.