>>I have this:
>>
>>

>>
>>var query = from g in root.Groups
>>            from r in g.Rules
>>            from c in r.Conditions
>>            from a in c.Actions
>>            where g.Rules != null
>>            where r.Conditions != null
>>            where c.Actions != null
>>            where a.ActionID == ActionId
>>            select a;
>>
>>List<RuleAction> items = query.ToList();
>>RetVal = items[0];

>>
>>
>>It fails on the last line with "Object reference not set to an instance of an object" because the query returned no results.
>>
>>How do I test for this before attempting to convert the results to a list?
>
>Test the items for zero length? Maybe:

>
>RetVal = items.Count==0 ? null : items[0];

It's failing on this line:

List<RuleAction> items = query.ToList();