Get the coordinates of the inner wrapper

I use microstation, DGN 2D V7 Upgrade V8
I use C# language

When fitview it will align the map
I want to get the polygon coordinates that wrap the inner lines like the green line, is it possible?

Bentley.Interop.MicroStationDGN.View v = app.ActiveDesignFile.Views[1];
Point3d point = v.get_Origin();
Point3d point2 = v.get_Center();

The code I tried but not as expected