Feedback in a custom tool

Hi, i need to create my objects in this way:

  1. choose the tool from a toolbar.
  2. the user can move the cursor (a crossair) over the diagram.
  3. create my GoObject at the click.
    very similar to a CAD application.
    i extented the GoTool class, and work ok.
    Now the problem is give the feedback to the user while add objects to a GoSubGraph : some objects are not compatible with others, and i want to show the Cursors.No when the operation in not available for the GoObject under the cursor.
    I found some possible solutions (screen coordinates, conversion to doc coordinates) but i think it’s a commond problem, and probably there is a better way for do this.

Sure, that should be easy to do in an override of GoTool.DoMouseMove. Many of the example tools that override DoMouseMove just do so to modify some object that it is in the process of constructing. But for your situation, you just need to look at the object at returned by this.View.PickObject(true, false, this.LastInput.DocPoint, true) to decide whether to change the GoView’s Cursor.
Presumably in your DoMouseUp method you will also make the same check to decide whether or not to really create that new object.