SPChangeQuery, classe (Microsoft.SharePoint)

[SharePointPermissionAttribute(SecurityAction.LinkDemand, ObjectModel=true)] 
[SharePointPermissionAttribute(SecurityAction.InheritanceDemand, ObjectModel=true)] 
public sealed class SPChangeQuery

using System;
using Microsoft.SharePoint;

namespace Test
{
   class ConsoleApp
   {
      static void Main(string[] args)
      {
         using (SPSite siteCollection = new SPSite("http://localhost"))
         {
            using (SPWeb rootSite = siteCollection.RootWeb)
            {
               // Construct a query.
               SPChangeQuery query = new SPChangeQuery(false, false); 

               // object type 
               query.Group = true;

               // change type
               query.GroupMembershipAdd = true;

               // Get the users and groups for the site collection.
               SPUserCollection users = rootSite.AllUsers;
               SPGroupCollection groups = rootSite.Groups;

               // Convert to local time.
               SPTimeZone timeZone = rootSite.RegionalSettings.TimeZone;

               // total changes
               int total = 0;

               // Loop until we reach the end of the log.
               while (true)
               {
                  SPChangeCollection changes = siteCollection.GetChanges(query);
                  total += changes.Count; // running total

                  foreach (SPChangeGroup change in changes)
                  {
                     // Try to get the group name.
                     string groupName = String.Empty;
                     try
                     {
                        SPGroup group = groups.GetByID(change.Id);
                        groupName = group.Name;
                     }
                     catch (SPException)
                     {
                        groupName = "Unknown";
                     }

                     // Try to get the user name.
                     string loginName = String.Empty;
                     try
                     {
                        SPUser user = users.GetByID(change.UserId);
                        loginName = user.LoginName;
                     }
                     catch (SPException)
                     {
                        loginName = "Unknown";
                     }

                     // Write to the console.
                     Console.WriteLine("\nDate: {0}", 
                          timeZone.UTCToLocalTime(change.Time).ToString());
                     Console.WriteLine("{0} was added to the {1} group.", 
                          loginName, groupName);
                  }

                  // Break out of loop if we have the last batch.
                  if (changes.Count < SPChangeCollection.CountLimit)
                     break;

                  // Otherwise, go get another batch.
                  query.ChangeTokenStart = changes.LastChangeToken;
               }

               Console.WriteLine("\nTotal changes = {0:#,#}", total);
            }
         }
         Console.Write("\nPress ENTER to continue...");
         Console.ReadLine();
      }
   }
}