CNiGraph::Annotations

   CNiAnnotation annotation = graph.Annotations.Add();
   annotation.Name = _T("Annotation01");
   annotation.Visible = true;

Or:

   CNiAnnotation annotation = graph.Annotations.Item(1);
   annotation.Name = _T("Annotation01");
   annotation.Visible = true;

If you do not initialize a CNiAnnotation object from an existing object, a CNiObjectNotInUsableState exception will be thrown when you attempt to manipulate the instance of the CNiAnnotation. For example:

   CNiAnnotation annotation;

   // This will throw a CNiObjectNotInUsableState exception because
   // the CNiAnnotation object was not initialized from an existing
   // object.
   annotation.Name = _T("Annotation01");