I have a windows service I wrote and I want it to raise an event when a certain condition exists.
I want my Windows form application to receive those events. Is this possible?
This service has to run when all users are logged off, but when they log in and start the app, I want it to begin receiving events from the service.
The simplest way would be to create a WCF endpoint in the service. Your applications would connect to that and then use a normal event delegate for information handling from the service.
This also will allow multiple clients and also remote clients, if necessary
For very old code there is .NET remoting, but better to update the code to use newer frameworks if possible.