using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Windows.Forms;

using System.Text;

using Autodesk.Navisworks.Api.Controls;

      static public string WriteSelectionSetContent(SavedItem item, string label, string lineText)
      {
         //set the output
         string output = lineText + "+ " + label + "\n";

         //See if this SavedItem is a GroupItem
         if (item.IsGroup)
         {
            //Indent the lines below this item
            lineText += "   ";

            //iterate the children and output
            foreach (SavedItem childItem in ((GroupItem)item).Children)
            {
               output += WriteSelectionSetContent(childItem, childItem.DisplayName, lineText);
            }
         }

         //return the node information
         return output;
      }

      /// <summary>
      /// Outputs to a message box the structure of the selection sets
      /// </summary>
      static public void ListSelectionSets()
      {
         //build output string for display
         string output =
            WriteSelectionSetContent(
            Autodesk.Navisworks.Api.Application.ActiveDocument.SelectionSets.RootItem,
            Autodesk.Navisworks.Api.Application.ActiveDocument.Title,
            "");

         //output in a message box
         MessageBox.Show(output);
      }

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Windows.Forms;

using System.Text;

using Autodesk.Navisworks.Api.Controls;

      static public void TestSavedItemReference()
      {
         //first check we have some data to test this with
         if (Autodesk.Navisworks.Api.Application.ActiveDocument.SelectionSets.RootItem.Children.Count > 0)
         {
            //get the first child item
            SavedItem item = Autodesk.Navisworks.Api.Application.ActiveDocument.SelectionSets.RootItem.Children[0];

            //create the SavedItemReference
            SavedItemReference reference =
               Autodesk.Navisworks.Api.Application.ActiveDocument.SelectionSets.CreateReference(item);

            //check the resolved reference
            if (Autodesk.Navisworks.Api.Application.ActiveDocument.SelectionSets.ResolveReference(reference)
               == Autodesk.Navisworks.Api.Application.ActiveDocument.SelectionSets.RootItem.Children[0])
            {
               MessageBox.Show("resolved item matches the first child item");
            }

            //remove the SavedItem
            bool val = Autodesk.Navisworks.Api.Application.ActiveDocument.SelectionSets.Remove(item);

            //check resolved reference is no longer valid
            if (Autodesk.Navisworks.Api.Application.ActiveDocument.SelectionSets.ResolveReference(reference)
               == null)
            {
               MessageBox.Show("SavedItem no longer exists");
            }
         }
      }