Microsoft Exchange Folders.findItems results limited to a 1000

Question

I am trying to get a list of contacts from a contacts folder in microsoft exchange.
the results is only returning a 1000 items even when there is more items in the folder.
Here is my code.

FindFoldersResults r = service.FindFolders(new FolderId(WellKnownFolderName.PublicFoldersRoot), new FolderView(10));
     Folder folder = getFolder("test", r.Folders);
     ContactsFolder contactsfolder = ContactsFolder.Bind(service, new FolderId(folder.Id.ToString()), new PropertySet(BasePropertySet.IdOnly, FolderSchema.TotalCount));        
     FindItemsResults<Item> items = folder.FindItems(new ItemView(contactsfolder.TotalCount));   

how can I get it to return all the items?

Answer 1

As the article referenced by Jason suggests, paging is key. Here is the code I am using against the Office365 Exchange Server to get a list of all e-mails in a given folder (over 20,000 e-mails, works very fast with page size 100):

            // via https://msdn.microsoft.com/en-us/library/office/dn592093(v=exchg.150).aspx
            int pageSize = 100;
            int offset = 0;
            ItemView view = new ItemView(pageSize + 1, offset);
            view.PropertySet = new PropertySet(ItemSchema.Subject, ItemSchema.DateTimeSent);
            view.OrderBy.Add(ItemSchema.DateTimeReceived, SortDirection.Descending);
            view.Traversal = ItemTraversal.Shallow;

            bool moreItems = true;
            ItemId anchorId = null;

            while (moreItems)
            {
                FindItemsResults<Item> results = service.FindItems(buildsFolderId, view);
                moreItems = results.MoreAvailable;
                if (moreItems && anchorId != null)
                {
                    // Check the first result to make sure it matches
                    // the last result (anchor) from the previous page.
                    // If it doesn't, that means that something was added
                    // or deleted since you started the search.
                    if (results.Items.First<Item>().Id != anchorId)
                    {
                        Console.Error.WriteLine("The collection has changed while paging. Some results may be missed.");
                    }
                }

                if (moreItems)
                {
                    view.Offset += pageSize;
                }

                anchorId = results.Items.Last<Item>().Id;

                // Because you’re including an additional item on the end of your results
                // as an anchor, you don't want to display it.
                // Set the number to loop as the smaller value between
                // the number of items in the collection and the page size.
                int displayCount = results.Items.Count > pageSize ? pageSize : results.Items.Count;

                for (int i = 0; i < displayCount; i++)
                {
                    Item item = results.Items[i];

                    Console.WriteLine("[" + item.DateTimeSent + "] " + item.Subject);
                }

                Console.Error.WriteLine("Current offset: {0}/{1}", view.Offset, folder.TotalCount);
            }