I have created a custom service using Visual Studio 2019. In the OnStart function, I call a function that verifies the parameters and values in the config file are correct. If they are not, it throws a custom exception which writes to the eventlog, then the service dies. Windows pops up a message The [custom service name] service on local computer started and then stopped... when this occurs. Can I prevent the windows pop up? Can I customize its message? Or am I aborting the start using the wrong technique? help greatly appreciated.

You asked a similar question about stopping a service from OnStart here - https://learn.microsoft.com/en-us/answers/questions/1058630/custom-service-stop In that thread I commented "Checking for resource availability in OnStart, allowing the service to start, and then spinning up a thread to call Stop() (instead of a thread to do the service's tasks) worked to stop the service gracefully without generating an error." You can use the same method to solve this problem.

How to shutdown a custom service from OnStart function in c#

Accepted answer

RLWA32 46,376 Reputation points

2023-01-13T23:46:34.0766667+00:00

You asked a similar question about stopping a service from OnStart here - https://learn.microsoft.com/en-us/answers/questions/1058630/custom-service-stop

In that thread I commented "Checking for resource availability in OnStart, allowing the service to start, and then spinning up a thread to call Stop() (instead of a thread to do the service's tasks) worked to stop the service gracefully without generating an error."

You can use the same method to solve this problem.
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1 person found this answer helpful.
Darryl Hoar 181 Reputation points

2023-01-16T21:23:48.8566667+00:00

OK. Thats true. So you are saying that in the OnStart function I should spin up a thread when the error condition (invalid parameter values) is thrown. In the thread body I should call OnStop. Is that what you mean ?

RLWA32 46,376 Reputation points

2023-01-16T22:26:27.6833333+00:00

Depending on your needs you may not need to throw an exception. Following sample shows testing for availability of a resource (i.e., file existence) and stopping the service if the resource is not available. The demo queues a work item to a thread pool thread instead of creating a new one.

The code that sets the duration of a call to Thread.Sleep in the OnStart method is used to demonstrate that even though the service is stopped gracefully the services gui may display a dialog box if the service stops too quickly right after it is started. I'm assuming that you wouldn't want that dialog box displayed. If you pass a small duration, say 500 milliseconds, you can see the dialog. I found that a 2000 millisecond delay was sufficient to prevent this but you may want to test that for yourself.

Note that ServiceStopper calls the service's Stop().

protected override void OnStart(string[] args) { // Log a service start message to the Application log. eventLog1.WriteEntry("TestService in OnStart."); if (!File.Exists(resourceNeeded)) { int iPause; if (args.Length == 0 || !int.TryParse(args[0], out iPause)) { iPause = 2000; } ThreadPool.QueueUserWorkItem(new WaitCallback(ServiceStopper), iPause); } else { // Queue the main service function for execution in a worker thread. ThreadPool.QueueUserWorkItem(new WaitCallback(WorkerThread)); } } private void ServiceStopper(object state) { Thread.Sleep((int) state); // Pause to allow service to return SERVICE_RUNNING before calling Stop() eventLog1.WriteEntry($"Resource {resourceNeeded} not available. ({(int) state})"); stoppedEvent.Set(); Stop(); }

Message box displayed by services gui if ServiceStopper delay is too short

RLWA32 46,376 Reputation points

2023-01-16T23:36:28.59+00:00

What does stoppedEvent.Set() do ?

When the running TestService demo service is stopped its OnStop() method waits on an event object which ordinarily would be signaled by WorkerThread right before it exits. This lets OnStop() wait for all work to be finished and resources to be cleaned up before processing continues and the service process exits.

When stopping the service by using ServiceStopper it is necessary to call stoppedEvent.Set() to simulate what would happen during normal processing.

Darryl Hoar 181 Reputation points

2023-01-17T15:52:18.4766667+00:00

Sorry to be thick. stoppedEvent is of type StoppedEvent? If so, where is System.Fabric.Chaos.Datastructures ?

RLWA32 46,376 Reputation points

2023-01-17T16:10:57.1033333+00:00

stoppedEvent is a variable of type System.Threading.ManualResetEvent.

https://learn.microsoft.com/en-us/dotnet/api/system.threading.manualresetevent?view=netframework-4.8

RLWA32 46,376 Reputation points

2023-01-17T16:56:51.98+00:00

The stoppedEvent variable is initialized in the service class (class derived from ServiceBase) constructor.

Instead of asking your questions by creating new answers I suggest that you use comments for your followup questions and convert the existing inquires from answers to comments. Answers are supposed to be used for solutions, not for asking new questions or clarification of information previously provided.

Darryl Hoar 181 Reputation points

2023-01-17T17:06:12.27+00:00

Thanks! Quite helpful.

What does stoppedEvent.Set() do ?

Darryl Hoar 181 Reputation points

2023-01-17T17:06:52.6733333+00:00

is the System.Threading.ManualResetEvent stoppedEvent = new ManualResetEvent(false) placed in the OnStart, ServiceStopper or somewhere else?

RLWA32 46,376 Reputation points

2023-01-19T09:51:47.61+00:00

@Darryl Hoar Have you tried to implement the solution that has been discussed?

Darryl Hoar 181 Reputation points

2023-01-19T13:58:18.78+00:00

Yes. I was able to get it to work. Thank you very much. Will mark as accepted answer.
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