/// <summary>Returns a string that represents the current object.</summary>
        /// <returns>A string that represents the current object.</returns>
        public override string ToString()
        {
            string baseFilterPresentation = _baseFilter != null?_baseFilter.ToString() : string.Empty;

            // The returned string is used in de DebuggerDisplay.
            if (!string.IsNullOrEmpty(baseFilterPresentation))
            {
                return(baseFilterPresentation + ", " + _predicate);
            }

            return(_predicate.ToString());
        }