Add Comment to Assembly Component Example (C#)

//----------------------------------------------------------------------------
// Preconditions:
// 1. Open an assembly document.
// 2. Select a component in the FeatureManager design tree.
// 3. Open an Immediate window.
//
// Postconditions: A comment about the selected component is added to the
// document's Comments folder.
// ---------------------------------------------------------------------------
using SolidWorks.Interop.sldworks;
using SolidWorks.Interop.swconst;
using System.Runtime.InteropServices;
using System;

namespace AddComment_C_.csproj
{
    public partial class SolidWorksMacro
    {

        public void Main()
        {
            ModelDoc2 swModel;
            SelectionMgr swSelMgr;
            ModelDocExtension swModelDocExt;
            Component2 selComp;
            String selCompName;
            Comment newComment;

            swModel = (ModelDoc2)swApp.ActiveDoc;
            swSelMgr = (SelectionMgr)swModel.SelectionManager;
            swModelDocExt = swModel.Extension;

            selComp = (Component2)swSelMgr.GetSelectedObjectsComponent4(1, -1);
            selCompName = selComp.Name2;

            newComment = swModelDocExt.AddComment("This component's name is " + selCompName);

        }

        public SldWorks swApp;
    }
}