private void VisitOrderBy(LambdaExpression expression, bool descending)
{
var propertyInfo = ((MemberExpression)expression.Body).Member as PropertyInfo;
var fieldInfo = ((MemberExpression)expression.Body).Member as FieldInfo;
var expressionMemberInfo = GetMember(expression.Body);
var type = propertyInfo != null
? propertyInfo.PropertyType
: (fieldInfo != null ? fieldInfo.FieldType : typeof(object));
luceneQuery.AddOrder(expressionMemberInfo.Path, descending, type);
}