CODEWITHSUNDEEP
c#entity-frameworklinq
Ivan
Ivan

Reputation: 67

LINQ query to Entity List within a List

I have a many-to-many relationship between two entities, Services and Facilities. I have a List<int> with the ID's of the selected facilities and I need to retrieve the services for each facility.

I tried this 

 Dictionary<int, List<Service>> Dic = new Dictionary<int, List<Service>>();

        foreach (var id in facilities)
        {
            Dic.Add(id,  _context.Services.Where(x => x.Facilities.Where(y => y.Id == id)));
        }

But all I got was this error:

Cannot implicitly convert type 'System.Collections.Generic.IEnumerable' to 'bool'

What's wrong with this code?

Upvotes: 2

Views: 1729

Answers (3)

ocuenca
ocuenca

Reputation: 39376

But, why not start with the Falicities:

var Dic= _context.Facilities.Where(f=>facilities.Contains(f.Id))
                            .ToDictionary(f=>f.Id,f.Services.ToList());

Upvotes: 2

tenbits
tenbits

Reputation: 8018

I would also suggest do not make the SQL requests within a loop. Better select all Services, which contain your Facilities, and then map them to a Dictionary<id,List<Service>

 var services = _ctx
    .Services 
    .Where(x => x.Facilities.Select(y => y.Id).Intersect(facilities).Any())
    .ToList();

facilities
    .Select(id => new { 
        Id = id, 
        Services = services.Where(service => service.Facilities.Any(y => y.Id == id)).ToList()
    })
    .ToDictionary(x => x.Id, x => x.Services);

Upvotes: 0

James Dev
James Dev

Reputation: 3009

 Dictionary<int, List<Service>> Dic = new Dictionary<int, List<Service>>();

    foreach (var id in facilities)
    {
        Dic.Add(id,  _context.Services.Where(x => x.Facilities.Any(y => y.Id == id)).ToList());
    }

Upvotes: 2

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