How can i enable the rulers for the diagram.

Kind regards Michi

The easiest approach is to replace your GoView with a GoDrawView. That control inherits from GoView and is in the Northwoods.Go.Draw.dll.

It also replaces some of the standard tools with customized ones that control the cursors in those rulers.
The implementation of GoDrawView and the customized tools could easily be implemented by anyone, and can easily be further adapted for most requirements.