Preview geometry from custom class

Hi, I’m trying to preview data from a custom class I’ve written. However, as soon as I include it in my code, Grasshopper just freezes up (it goes pale white, similar to the behavior when calling an infinite loop). Here’s what I’m doing:

The custom class I derive from GH_Goo<object> and I make it inherit from IGH_PreviewObject. I override IsPreviewCapable, ClippingBox, Hidden, DrawViewportWires and I create some PreviewArgs from some lines created by the class, as shown in the code below.

In my component I then call DrawViewportWires and pass the PreviewArgs I created in the class. Is that the right thing to do?

    public class CustomClass : GH_Goo<object>, IGH_PreviewObject

    {

//GH_Goo stuff

//Custom Class stuff

        bool IGH_PreviewObject.IsPreviewCapable

        {

            get { return true; }

        }

        private BoundingBox boundingBox;

        private BoundingBox BoundingBox

        {

            get

            {

                List<Point3d> ptsPreview = new List<Point3d>();

                //add points to list

foreach (Point3d pt in pts) { ptsPreview.Add(pt); }

                boundingBox = new BoundingBox(ptsPreview);

                return boundingBox;

            }

        }

        BoundingBox IGH_PreviewObject.ClippingBox

        {

            get { return BoundingBox; }

        }

        bool IGH_PreviewObject.Hidden

        {

            get

            {

                return false;

            }

            set

            {

                //…

            }

        }

        void IGH_PreviewObject.DrawViewportWires(IGH_PreviewArgs ArgsWires)

        {

            //base.DrawViewportWires(ArgsWires); -what’s base with GH_Goo<object>?

            ArgsWires.Display.DrawLines(PreviewLines, Color.Red);

        }

        void IGH_PreviewObject.DrawViewportMeshes(IGH_PreviewArgs ArgsMeshes)

        {

            //base.DrawViewportWires(ArgsMeshes); -what’s base with GH_Goo<object>?

        }

        public IGH_PreviewArgs ArgsWires

        {

            get

            {

                ArgsWires.Display.DrawLines(PreviewLines, ArgsWires.WireColour);

                return ArgsWires;

            }

        }

        private List<Line> previewLines;

        public List<Line> PreviewLines

        {

            get

            {

                previewLines = new List<Line>();

                foreach (Line l in lines) { previewLines.Add(l); }

                return previewLines;

            }

        }

}

In the component which uses the class, I then call

CustomClass cl = new CustomClass();         

DrawViewportWires(cl.Args);

I’ve also tried 

cl.DrawViewportWires(cl.ArgsWires);

but I get the same error.

Also, I’ve tried putting all of the IGH_PreviewObject stuff into the component and collecting the “previewLines” in SolveInstance, which didn’t cause Grasshopper to freeze, but didn’t display anything either. Any help/pointers in the right direction would be greatly appreciated! Thanks, Daniel