Why would you want to use DirectX in a Service? Service are not normal applications, e.g. they might run in their own session/desktop, which is not viewable by the user. It is way safer and recommaned to move the DX code into a user application and let the service communicate with this application about what it should display.

With this question there are two main things to consider. The first is that a direct3d device needs to have a display or Visual component, and the second is that a windows service is designed to run in the background where there is no display availible to it.

So the answer is not it can not run in a service. If you would like to a have a visual component that displays information that is collected from a service, these would be two different applications and have a communications layer between them. Have a look at socket communication, or remoting..

@Bjoern: I guess you would want to use DirectX in a service for the same exact reasons you would want to run any other app :)  In the company I work for, we currently have 12 build servers performing various tasks for our game, and mostly I want everything to restart automatically when they reboot (for example, after some Windows update was pushed), without any user having to log in.

Frederic