That's what I'd like to do: I need to edit some DGN-files, but I need to do it so that the user don't see the opening MS window and all the operations done by my application's code.
So, in fact, I have 2 questions:
Depending on specifically what you are looking to do, you might be able to take advantage of something called an InitApp, which can start MicroStation in "non-graphics" mode (or even work within a MicroStation session that has had MicroStation initialized). A number of applications that are delivered with MicroStation perform just that way and there is example source code delivered with the MicroStation SDK called InitApp that might be worth investigating.