Comments for The ways of Mauri

Comment on Tutorial – Building a Windows Service application in C# by Angela

Angela — Wed, 22 Feb 2012 15:24:00 +0000

I hope this makes sense, I used this skelton to create a windows service that queries 2 database work tables, one that holds raw blob data that needs to be decompressed and converted from RTF to Plain Text/HTML and one that is it’s parent table. I query the parent work table and put the results into a datatable, and close the conn. The service loops through the datatable, and queries a child work table that holds the raw blobs. The results are then inserted/updated into their permanent decompressed/converted tables. Once this is done, I go back to the raw work tables and delete the rows. Then I put the service to sleep for 10 secs to allow the work tables to fill back up. I open/close a connection for each database call. The problem I’m having is excessive blocking in the SQL Server 2005 database when I delete the processed rows from the work tables. I used Activity Monitor to view the processes that are being generated and I see several connections being made to delete the rows? This confuses me because I close the connection after each database call.

Comment on Tutorial – Building a Windows Service application in C# by Anil kumar

Anil kumar — Tue, 31 Jan 2012 03:54:17 +0000

Great tuts keep going

Comment on Tutorial – Building a Windows Service application in C# by mvanbeusekom

mvanbeusekom — Wed, 25 Jan 2012 14:04:00 +0000

Hi CSDull,

I am glad you found the tutorial helpful.

In remark to your questions there are several solutions of course. Below I will try to give a possible example solution (the full source can be found here, Note: I have upgraded the solution to Visual Studio 2008)

First add a new constructor to the ‘EventLoggerApp’ which will initialize the ‘EventLog’ class and remove the code from the ‘Start()’ method, like this:

public EventLoggerApp()
{
  // Check if the EventLoggerService Event Log Source exists, when not
  // create it
  if (!EventLog.SourceExists("EventLoggerSource"))
    EventLog.CreateEventSource("EventLoggerSource", "Event Logger");
 
  _log = new EventLog();
  _log.Source = "EventLoggerSource";
}

New ‘Start()’ method will look like this:

public void Start()
{
  _thread = new Thread(new ThreadStart(Execute));
  _thread.Start();
}

The next step is to modify the ‘Execute()’ method to run according to a schedule, an example solution could look like this:

private void Execute()
{
  // Loop until the thread gets aborted
  try
  {
    DateTime startTime = default(DateTime);
	double intervalInMinutes = 0;
 
	if (!DateTime.TryParse(ConfigurationManager.AppSettings["StartTime"], out startTime))
	{
	  _log.WriteEntry("ERROR (EventLoggerApp.Execute): Unable to parse start date as datetime, check configuration.");
	  return;
	}
 
	if (!double.TryParse(ConfigurationManager.AppSettings["IntervalInMinutes"], out intervalInMinutes))
	{
	  _log.WriteEntry("ERROR (EventLoggerApp.Execute): Unable to parse interval as integer, check configuration.");
	  return;
	}
 
	DateTime nextRunDate = startTime;
 
	while (true)
	{
	  if (nextRunDate.CompareTo(DateTime.Now) <= 0)
	  {
	    // Call the RunOnce method to execute the application logic
		RunOnce();
 
		// Calculate the next time to run
		nextRunDate = nextRunDate.AddMinutes(intervalInMinutes);
	  }
 
	  // Sleep for ten seconds
	  Thread.Sleep(10000);
	}
  }
  catch (ThreadAbortException)
  {
    _log.WriteEntry("INFO (EventLoggerApp.Execute): Thread aborted.");
  }
}

Next add the ‘RunOnce()’ method to the ‘EventLoggerApp’ like this:

public void RunOnce()
{
  // TODO: Put you application logic here (like create the log entry in the eventlogger example)
  _log.WriteEntry(string.Format("INFO (EventLoggerApp.Execute): Current time is: {0}.", DateTime.Now.ToString("HH:mm:ss")));
}

The last thing to do is to add an Application Configuration File to the project and add the ‘StartTime’ and ‘IntervalInMinutes’ settings like this:

 version="1.0" encoding="utf-8" ?>
>
  >
     key="StartTime" value="14:00" />
     key="IntervalInMinutes" value="720" />
  >
>

Now to run the application manually you can simply run it from the Command Line. And by changing the ‘Program’ class a little we can simple type ‘run’ followed by a return to make the application logic run:

static void Main(string[] args)
{
  if (args.Length > 0 && args[0].ToLower() == "/console")
  {
	AllocConsole();
 
    EventLoggerApp app = new EventLoggerApp();
    bool keepRunning = true;
	string input = string.Empty;
 
	Console.WriteLine("Eventlogger Console started. Type one of the following commands:");
    Console.WriteLine("- run: to execute the application logic once manually;");
    Console.WriteLine("- scheduled: to execute the application according to the schedule;");
    Console.WriteLine("- exit: to exit the application.");
 
	// Wait for the user to exit the application                
    while (keepRunning)
    {
      input = Console.ReadLine();
 
      switch (input.ToLower())
      { 
        case "run":
          app.RunOnce();
          break;
        case "scheduled":
          app.Start();
          break;
        case "exit":
          keepRunning = false;
          break;
      }
    }
 
    // Stop the application.
    app.Stop();
  }
  else
  {
    // Initialize and run the service
    ServiceBase[] ServicesToRun;
    ServicesToRun = new ServiceBase[] { new EventLoggerService() };
    ServiceBase.Run(ServicesToRun);
  }
}

I hope this helps, let me know if you have more questions.

Cheers, Mauri

Comment on Tutorial – Building a Windows Service application in C# by CSDull33

CSDull33 — Tue, 24 Jan 2012 20:07:02 +0000

This tutorial was very helpful but I have one question. Like Chetana, I want my service to run twice a day, but would also like the functionality to have it run on demand on occasions. Do you have any suggestion on how I might implement this?

Comment on Tutorial – Building a Windows Service application in C# by William Seaward

William Seaward — Sun, 22 Jan 2012 12:04:01 +0000

I loved your article and thank you very much for writting it. Are you still considering updating this with the addition of reading from the configuration file?

Comment on Tutorial – Building a Windows Service application in C# by Ahmed

Ahmed — Tue, 10 Jan 2012 06:10:33 +0000

Really amazing tutorial thanks. I was a little lost on where to start but this was really great. Thanks

I did get some errors

“The source was not found, but some or all event logs could not be searched. Inaccessible logs: Security.”

Looks like a permission thing but not sure on where to look

Comment on Tutorial – Building a Windows Service application in C# by TilakG

TilakG — Wed, 28 Dec 2011 07:32:43 +0000

Nice tutorial. Any body can create the windows service after reading this tutorial.
I need more details about the window service to incorporate a windows application as a service with the interactive mode and loggings.

Comment on Tutorial – Building a Windows Service application in C# by Jose

Jose — Fri, 16 Dec 2011 19:12:31 +0000

Great tutorial. Superior to other alternatives in the internet as of Dec 2011. I would also definitly buy a book about windows services if you wrote it like this.

Comment on Tutorial – Building a Windows Service application in C# by Prof g

Prof g — Thu, 08 Dec 2011 19:21:44 +0000

Very nicely done Mauri…you have gift for teaching. Very easy to read, follow. Look forward to seeing more of your work on the web.

Prof g

Comment on Tutorial – Building a Windows Service application in C# by mvanbeusekom

mvanbeusekom — Wed, 30 Nov 2011 12:41:01 +0000

Hi Neeraj, Thank you for the nice comments. To answer your question, a Windows Service application doesn't have a UI layer since the process is run on the background. This means you cannot use the standard methods to show a messagebox as you would when building a WinForms application for instance. However there are some possibilities to get some interaction going, maybe you will find these links useful: