private void DeleteAllListItems(SPList currentList, SPWeb web)
        {
            StringBuilder sbDelete = new StringBuilder();
            sbDelete.Append("<?xml version=\"1.0\" encoding=\"UTF-8\"?><Batch>");

            foreach (SPListItem item in currentList.Items)
            {
                sbDelete.Append("<Method>");
                sbDelete.Append("<SetList Scope=\"Request\">" + currentList.ID + "</SetList>");
                sbDelete.Append("<SetVar Name=\"ID\">" + item.ID.ToString() + "</SetVar>");
                sbDelete.Append("<SetVar Name=\"Cmd\">Delete</SetVar>");
                sbDelete.Append("</Method>");
            }

            sbDelete.Append("</Batch>");

            try
            {
                web.ProcessBatchData(sbDelete.ToString()); 
            }
            catch (Exception ex)
            {
                Console.WriteLine("Delete failed: " + ex.Message);
                throw;
            }