/// <summary>
        /// Returns a string that represents the current DataErrorMessage object fields.
        /// </summary>
        /// <param name="indentLevel">The indentation level used for tracing the message members.</param>
        /// <returns>
        /// A string that represents the current DataErrorMessage object fields.
        /// </returns>
        protected override string ToStringFields(int indentLevel)
        {
            string sep   = GetFieldSeparator(indentLevel);
            string value = base.ToStringFields(indentLevel);

            value += sep + "cause = " + (cause != null ? cause.ToString(indentLevel) : null);
            value += sep + "serverObject = " + serverObject;
            value += sep + "propertyNames = " + BodyToString(propertyNames, indentLevel);
            return(value);
        }