I'm trying to figure out if there's a way to use SetWindowsHookEx and be able to affect apps that are run with Admin rights on Vista, with UAC enabled. This is an app that will need to add a small button to the caption bar of other windows to enable some multi-monitor-aware handling. I would have thought this couldn't be done, but I've seen one app that appears to do this. As far as I can tell, this other apps is not being run with Admin rights, and yet it can affect all apps in the system, including those with Admin privilege.
It would seem that there's a way to do this, then, but I'm at a loss on how. My app only needs to be able to draw on window title bars and be able to affect their movement and size. I don't need to do anything else.
You can't, as administrative processes are isolated from non-administrative processes running on the same user desktop. You can't even drag and drop between admin and non-admin processes.
This is an in-dept analysis: http://technet.microsoft.com/en-us/magazine/2007.06.uac.aspx
About the application you are referencing, it probably uses some administrative code running in background (usually as a service) so it can interact with administrative processes.
来源：https://stackoverflow.com/questions/3169675/how-to-use-setwindowshookex-in-vista-and-hook-admin-apps-with-uac