left join linq - object reference is null

Question

I have this query below which works fine in LINQPad but it's giving me an error in my project

var query = from c in corps
            join cl in corpsPlaces on c.CorpID equals cl.CorpID into cl_join
            from cl in cl_join.DefaultIfEmpty()
            join l in places on cl.PlaceID equals l.PlaceID into l_join
            from l in l_join.DefaultIfEmpty()
            select new
            {
             c.CorpID,
             Name =  l.PlaceName == null ? c.CorpName : (l.PlaceName + " - " + c.CropName)
            };

I know I am using left join and name can be null therefore I used that conditional operator and the error line

 join l in places on cl.PlaceID equals l.PlaceID into l_join

I'm using EF 6, if it matters.

Any help will be appreciated

You need give us some background on your database so we can help you. And use grammar and spelling so people are more likely to answer. How to create a minimal, complete, verifiable example [mcve] — noɥʇʎԀʎzɐɹƆ, Jun 27 '16 at 19:40
it's not a problem of understanding, but of quality. for example, you use "i" instead of "I". you also say "im using ef 6 if it matters" instead of "I'm using ef 6 if it matters". What's ef? — noɥʇʎԀʎzɐɹƆ, Jun 27 '16 at 19:45
not to be a grammar nazi, just trying to get you more answers — noɥʇʎԀʎzɐɹƆ, Jun 27 '16 at 19:45
We need you to get further in the problem-solving than just "I have a null reference". Please provide a good [mcve] that reliably reproduces the problem, as well as explain _specifically_ what is null, what you've done already to try to resolve the null reference, and what _specific_ difficulty you are still having in fixing the problem. — Peter Duniho, Jun 28 '16 at 07:22

score 0 · Answer 1 · edited May 23 '17 at 12:08

0

You get a null reference exception for the cl.PlaceID in the second left join right? The reason in that cl is null and so cl.PlaceID results in a NullReferenceException.

You should use GroupJoin to perform so. Please look at this question

edited May 23 '17 at 12:08

Community

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answered Jun 27 '16 at 19:57

Gilad Green

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left join linq - object reference is null

1 Answers1