Purge Lists CSOM SharePoint

private void Purge()
{
    try
    {
        using (ClientContext ctx = new ClientContext(sharePointSiteUrl))
        {
            ctx.Credentials = new SharePointOnlineCredentials(userName, password);

            var web = ctx.Web;
            ctx.Load(web, w => w.Title);
            ctx.ExecuteQuery();
            this.statusLabel.Text = string.Format("Purge '{0}'...", web.Title);
            var listsToPurge = <Ensemble des listes à purger>;
            int totalItemCount = this.spListsList.CheckedItems.Cast<MyListItem>().Sum(i => i.ItemCount);
            this.progressBar.Value = 0;
            this.progressBar.Maximum = totalItemCount;
            foreach (MyListItem listToPurge in listsToPurge)
            {
                this.PurgeList(ctx, listToPurge);
            }

            var lists = web.Lists;
            ctx.Load(lists, ls => ls.Include(l => l.Title), ls => ls.Include(l => l.ItemCount));
            ctx.ExecuteQuery();

            this.spListsList.Items.Clear();
            foreach (List list in lists)
            {
                this.spListsList.Items.Add(new MyListItem() { Title = list.Title, ItemCount = list.ItemCount });
            }
        }
    }
    catch (Exception e)
    {
        MessageBox.Show(string.Format("Exception has occured : {0}", e), "Exception in purging", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

private void PurgeList(ClientContext ctx, MyListItem listToPurge)
{
    try
    {
        List spList = ctx.Web.Lists.GetByTitle(listToPurge.Title);
        ctx.Load(spList);
        CamlQuery itemsIdQuery = CamlQuery.CreateAllItemsQuery(50, new string[] { "Id" });

        int lastIdWithException = -1;
        int maxBatchNumber = 1000;

        while (--maxBatchNumber > 0)
        {
            var itemBatch = spList.GetItems(itemsIdQuery);
            ctx.Load(itemBatch);
            ctx.ExecuteQuery();

            if (itemBatch.Count == 0)
            {
                return;
            }

            foreach (var item in itemBatch)
            {
                try
                {
                    this.DeleteItemAndAttachments(ctx, spList, item.Id);
                }
                catch (Exception)
                {
                    if (item.Id == lastIdWithException)
                    {
                        throw;
                    }

                    lastIdWithException = item.Id;
                }

                progressBar.PerformStep();
                Application.DoEvents();
            }
        }

        //ctx.ExecuteQuery();
    }
    catch (Exception e)
    {
        MessageBox.Show(string.Format("Exception has occured : {0}", e), "Exception in purging list", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

private void DeleteItemAndAttachments(ClientContext ctx, List spList, int id)
{
    ListItem itemToDelete = spList.GetItemById(id);
    ctx.Load(itemToDelete, i => i.AttachmentFiles);
    ctx.ExecuteQuery();

    for (int attachmentIndex = itemToDelete.AttachmentFiles.Count - 1; attachmentIndex >= 0; attachmentIndex--)
    {
        itemToDelete.AttachmentFiles[attachmentIndex].DeleteObject();
    }

    itemToDelete.DeleteObject();
}