/// <summary>
        /// Add an extended filter to the list
        /// </summary>
        /// <param name="extensionInfo">The extension method that should be added to the filter</param>
        public static void AddExtendedFilter(IQueryFilterExtension extensionInfo)
        {
            string methName = extensionInfo.Name;

            lock (s_extensionMethods)
                if (!s_extensionMethods.ContainsKey(methName))
                {
                    s_extensionMethods.Add(methName, extensionInfo);
                }
        }
        /// <summary>
        /// Get an extended filter name
        /// </summary>
        public static IQueryFilterExtension GetExtendedFilter(String name)
        {
            if (s_extensionMethods.Count == 0)
            {
                InitializeFilters();
            }
            IQueryFilterExtension retVal = null;

            s_extensionMethods.TryGetValue(name, out retVal);
            return(retVal);
        }