作为Windows服务运行时，如何获取活动监视器的数量？ C ++

Question

I have ran into an issue when retrieving the number of active monitors while the exe is running as a windows service. I have tried using EnumDisplayDevices and GetSystemMetrics(SM_CMONITROS) to get the number of monitors, these two methods woulds give me the correct number of monitors when running them as console mode (meaning initiated by the user), but when I register the exe as a service and run it through the windows service, the number of monitors that was reported turned out to be incorrect.

Is there any other way to determine the number of active monitors while running as a windows service? Or any other work around? Thanks in advance!

Answer 1

Services are not allowed to interact with the user desktop for security reason. Therefore they are running in their virtual desktop which has nothing to do with the physical one. You can try the following. In the service list of the service manager. Rightclick your service, go to properties and there to "Log On". There you can change the account the service is using. With the "Local System account" you can check the "Allow service to interact with desktop". I didn't try that my self. But for interacting the service has to get the access to the "real" desktop and therefore the monitor count should be right.