Using DefaultIfEmpty in Linq - problem substituting a null value for a default value

Posted by FiveTools on Stack Overflow See other posts from Stack Overflow or by FiveTools
Published on 2010-05-21T17:56:50Z Indexed on 2010/05/21 18:00 UTC
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LINQ

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c#

I have questions that may or may not have a question_group

if all the questions do not have a question_group and if I use default if empty like this:

question_group defaultQuestion = new question_group {question_group_id = Guid.Empty};
questions.Select(x => x.question_group).DefaultIfEmpty(defaultQuestion).Distinct();

shouldn't I get an IEnumerable<question_group> containing only the default question_group that I defined? I get null.... what am I missing here?

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