LINQ To SQL exception: Local sequence cannot be used in LINQ to SQL implementation of query operators except the Contains operator

linqlinq-to-sql

Consider this LINQ To SQL query. It's intention is to take a string[] of search terms and apply the terms to a bunch of different fields on the SQL table:

string[] searchTerms = new string[] {"hello","world","foo"};
List<Cust> = db.Custs.Where(c => 
   searchTerms.Any(st => st.Equals(c.Email))
|| searchTerms.Any(st => st.Equals(c.FirstName))
|| searchTerms.Any(st => st.Equals(c.LastName))
|| searchTerms.Any(st => st.Equals(c.City))
|| searchTerms.Any(st => st.Equals(c.Postal))
|| searchTerms.Any(st => st.Equals(c.Phone))
|| searchTerms.Any(st => c.AddressLine1.Contains(st))
)
.ToList();

An exception is raised:

Local sequence cannot be used in LINQ to SQL implementation of query operators except the Contains() operator

Question:
Why is this exception raised, and how can the query be rewritten to avoid this exception?

Best Answer

Replace the usages of Any with Contains in your query. eg:

searchTerms.Contains(c.Email)

This should get the result you're looking for. It looks backwards, but it's correct- it'll generate an IN operator for each field inside a Contains with all the elements in searchTerms.

The AddressLine1 part won't work this way- you'll have to loop-generate the comparisons yourself with

c.addressLine1.Contains(...)

Something like PredicateBuilder can be helpful for this.

Related Solutions

C# – Local sequence cannot be used in LINQ to SQL implementations of query operators except the Contains operator

I basically reversed the join and it worked

var urunMD = from urunStokbilgileri in urunStok
             join urun in db.TBLP1URUNs
                       on urunStokbilgileri.UrunNo equals urun.ID
             join kategori in db.TBLP1URUNKATEGORIs
                       on urun.KATEGORIID equals kategori.ID
             ......

C# – Local sequence cannot be used in LINQ to SQL implementation of query operators except the Contains() operator

You can't use a Join between a SQL source and a local source. You'll need to bring the SQL data into memory before you can join them. In this case, you're not really doing a join since you only take the elements from the first collection, what you want is a select...where...selectid in query, which you can get using the Contains method.

 var SE = Shop.Sections.Where( s => obj.SectionObjects
                                       .Select( so => so.SectionId )
                                       .Contains( s.SectionId ))
                       .ToList();

Translates to

select * from Sections where sectionId in (...)

where the values for the in clause come from the list of ids in the collection of local objects.

Best Answer

Related Solutions

C# – Local sequence cannot be used in LINQ to SQL implementations of query operators except the Contains operator

C# – Local sequence cannot be used in LINQ to SQL implementation of query operators except the Contains() operator

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