R – How to call a windows service in a console application

Use the SC command, like this (you need to be on a command prompt to execute the commands in this post):

SC STOP shortservicename
SC DELETE shortservicename

Note: You need to run the command prompt as an administrator, not just logged in as the administrator, but also with administrative rights. If you get errors above about not having the necessary access rights to stop and/or delete the service, run the command prompt as an administrator. You can do this by searching for the command prompt on your start menu and then right-clicking and selecting "Run as administrator". Note to PowerShell users: sc is aliased to set-content. So sc delete service will actually create a file called delete with the content service. To do this in Powershell, use sc.exe delete service instead

If you need to find the short service name of a service, use the following command to generate a text file containing a list of services and their statuses:

SC QUERY state= all >"C:\Service List.txt"

For a more concise list, execute this command:

SC QUERY state= all | FIND "_NAME"

The short service name will be listed just above the display name, like this:

SERVICE_NAME: MyService
DISPLAY_NAME: My Special Service

And thus to delete that service:

SC STOP MyService
SC DELETE MyService

What's likely happening is that SignalData is indirectly changing the subscribers dictionary under the hood during the loop and leading to that message. You can verify this by changing

foreach(Subscriber s in subscribers.Values)

To

foreach(Subscriber s in subscribers.Values.ToList())

If I'm right, the problem will disappear.

Calling subscribers.Values.ToList() copies the values of subscribers.Values to a separate list at the start of the foreach. Nothing else has access to this list (it doesn't even have a variable name!), so nothing can modify it inside the loop.