How do you debug a Windows Service?

Question

I read the MSDN article on the topic. To quote:

Because a service must be run from within the context of the Services Control Manager rather than

Answer 1

In order to attach a debugger to the Windows Service, it needs to be started first. The reason why the service failed to start can be checked in Windows Event Log.

After that the process of attaching a debugger is pretty straight forward from Visual Studio Debug->Attach To Process.

Answer 2

Seems like the problem is with the user context. Let me confirm whether my assumptions are right.

1. When you say that the code works perfectly from console application, I assume you are executing the Console application under the same user which you had logged in.

2. When you say that the same code crashes while called from the windows service, I assume the service is running in "Local System" account in your development machine.

If both my assumptions are right, please try out the following steps.

1. In the services listing right-click your service, select properties and then "Log On" tab.

2. Select the option "This account" and provide the existing username and password.

3. Now try starting the service. It should now start without any errors.

Following could be the root cause of your error

1. If you are using SQL Server make sure you are not using SSPI authentication.

2. If you are trying to read any shared folder\resource which you don't have permission when using "local system" account.

3. If any of the required dependencies required by the application is in a different folder which the "Local System" user doesn't have permission to access.

4. If you are using VBA automation which wont work in "Local System" account.

5. Try disabling your firewall or antivirus.

Answer 3

What I've done is implemented by OnStart() to look something like this:

_myBusinessObject = new MyBusinessObject();

After the Business Object has been constructed, timers and IPC handlers do all the real (Service) work.

Doing it like this allows you to create a Forms/WPF application that call the same code above in the Form_Loaded handler. This way, debugging the Forms application is the exact same as debugging the Service.

The only issue is that if you are using app.config values, there will be a second app.config file that needs to be kept up-to-date.