I want to display the radius of drawing circle when user adds this figure on the map.

  1. User clicks on the icon.
  2. Then user begins drawing circle (I process the MouseDown event)

    IGeometry geom = Map.TrackCircle();

  3. When user clicks on the map, I draw this circle on the map (I get radius from TrackCircle and center from mouse coordinates).

I want to display radius on the map or in the bottom tooltip (like ArcMap) on the step 2 (TrackCircle).

I think I must process the event OnAfterDraw of the MapControl, but I do not know how (how can I know that user drawing circle and the radius of this circle?).

  • You mention MapControl, are you writing an application for Engine or an AddIn for desktop?
    – Hornbydd
    Commented Mar 23, 2015 at 17:05
  • application for Engine (arcobjects 10.1)
    – Oleg
    Commented Mar 24, 2015 at 6:19

1 Answer 1


The doc's say that TrackCircle does trigger OnMouseMove. Why not just track that and display the current radius where ever you want.

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