protected string GetFieldNameCached(Expression columnExpression)
        {
            string fieldName;

            if (FieldNameCache.ContainsKey(columnExpression))
            {
                fieldName = FieldNameCache[columnExpression];
            }
            else
            {
                fieldName = _expressionUtils.GetFieldName(columnExpression);
                FieldNameCache.Add(columnExpression, fieldName);
            }

            return(fieldName);
        }