How do I debug Windows services in Visual Studio?

Use the following code in service OnStart method:

System.Diagnostics.Debugger.Launch();

Choose the Visual Studio option from the pop up message.

Note: To use it in only Debug mode, a #if DEBUG compiler directive can be used, as follows. This will prevent accidental or debugging in release mode on a production server.

#if DEBUG
    System.Diagnostics.Debugger.Launch();
#endif

You can also try this.

1. Create your Windows service and install and start…. That is, Windows services must be running in your system.
2. While your service is running, go to the Debug menu, click on Attach Process (or process in old Visual Studio)
3. Find your running service, and then make sure the Show process from all users and Show processes in all sessions is selected, if not then select it.

4. Click the Attach button
5. Click OK
6. Click Close
7. Set a break point to your desirable location and wait for execute. It will debug automatic whenever your code reaches to that point.
8. Remember, put your breakpoint at reachable place, if it is onStart(), then stop and start the service again

(After a lot of googling, I found this in "How to debug the Windows Services in Visual Studio".)

You should separate out all the code that will do stuff from the service project into a separate project, and then make a test application that you can run and debug normally.

The service project would be just the shell needed to implement the service part of it.