Hi,
The bounds of a shape are in scene coordinates, so in order to get its bounds in screen coordinates you should first convert the scene coordinates to device coordinates using the drawing view's SceneToDevice transform and then convert the result to screen coordinates using the standard WinForms Control.PointToScreen method. Here's an example:
NRectangleF bounds = view.SceneToDevice.TransformBounds(shape.Bounds);
Point topLeft = view.PointToScreen(bounds.Location.Round().ToPoint());
Point bottomRight = view.PointToScreen(bounds.RightBottom.Round().ToPoint());
For more information about the coordinate systems used in Nevron Diagram for .NET, check out the Coordinate Systems documentation topic.