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 IteratePropertyCategoryDataPropertys()
      {
         //create a list to store the category names
         StringBuilder output = new StringBuilder();

         //check there is a valid ActiveDocument
         if (Autodesk.Navisworks.Api.Application.ActiveDocument != null &&
            !Autodesk.Navisworks.Api.Application.ActiveDocument.IsClear)
         {
            //iterate the ModelItems in the current selection
            foreach (ModelItem item in Autodesk.Navisworks.Api.Application.ActiveDocument.CurrentSelection.SelectedItems)
            {
               //iterate the item's PropertyCategory entries
               foreach (PropertyCategory category in item.PropertyCategories)
               {
                  //iterate over the DataPropertys
                  foreach (DataProperty dataProperty in category.Properties)
                  {
                     //add content for display
                     output.Append(string.Format(
                        "PropertyCategory: ({0} / {1})   DataProperty: CombinedName='{2}', Value='{3}'",
                        category.DisplayName, category.Name, dataProperty.CombinedName,
                        (dataProperty.Value == null ? "" : dataProperty.Value.ToString())));
                  }
               }
            }

            //output to the screen
            MessageBox.Show(output.ToString());
         }
      }