CODEWITHSUNDEEP
c#.netentity-frameworklinq-to-entitiesmany-to-many
finoutlook
finoutlook

Reputation: 2533

Many to Many select in LINQ to Entities

I have two tables Service and Provider. Between them is a joining table ServiceProvider which has only 2 fields - one for each of the two PKs. When added to the edmx the joining many-to-many table is abstracted away and can't be seen (as expected).

This is all fine except when I want to get Providers based on a given service. From this question:

it looks like the answer would be simply:

var query = from p in entities.Providers
            from s in entities.Services
            where s.Id == 15
            select p;

but this returns ALL providers. What am I doing wrong here?

Upvotes: 5

Views: 4380

Answers (4)

Boomer
Boomer

Reputation: 1478

You may try using join, like so:

entity.Providers.Join(entity.Services, c => c.ID, p => p.ID,(c, p) => new { Providers= c, Services= p })

Upvotes: -1

Maciej
Maciej

Reputation: 7961

Try this:

var res = from s in entities.Services
          where s.Id == 15
          select s.Provider;

EDIT

Corrected and tested the query on real-life model and data. It works now.

Upvotes: 2

halit
halit

Reputation: 1128

var query = entities.Providers.FirstOrDefault(p => p.Id == 15).Services.ToList();

Upvotes: 4

Rawling
Rawling

Reputation: 50114

Isn't it as simple as

var matchingProviders = entities.Services.Single(s=>s.Id==15).Providers;

Upvotes: 2

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