CODEWITHSUNDEEP
asp.net-mvclinqentity-framework
Bahman
Bahman

Reputation: 1064

"In clause" by LINQ to SQL

I want to use something like "In clause" of SQL SERVER. Here are my models:

public partial class StationEvaluationBooks
{
    public int StationEvaluationBookID { get; set; }
    public Nullable<int> StationEvaluationID { get; set; }

    public virtual StationEvaluation StationEvaluation { get; set; }
    ...
 }
public partial class StationEvaluation
{
    public StationEvaluation()
    {
        this.StationEvaluationBooks = new HashSet<StationEvaluationBooks>();
    }
    public int StationEvaluationID { get; set; }
    public virtual ICollection<StationEvaluationBooks> StationEvaluationBooks { get; set; }
    ...
 }

I used the following code to implement "In clause" by LINQ but I got error:

        StationsEntities db = new StationsEntities();

        var stationevaluations = db.StationEvaluation;
       //some conditions:
        stationevaluations = stationevaluations.Where(/*condition*/);
       ..

        var result = from c in db.StationEvaluationBooks
                       where stationevaluations.Contains(c.StationEvaluationID)
                       select c;

Error: 'System.Data.Entity.DbSet' does not contain a definition for 'Contains' and the best extension method overload 'System.Linq.ParallelEnumerable.Contains(System.Linq.ParallelQuery, TSource)' has some invalid arguments

EDIT: I want to get those books that are related to the selected evaluations in stationevaluations variable.

Upvotes: 2

Views: 1765

Answers (2)

Sergey Berezovskiy
Sergey Berezovskiy

Reputation: 236208

Getting books related to selected stations:

var ids = db.StationEvaluation.Where(/*condition*/)
            .Select(s => s.StationEvaluationID)
            .ToList();

var result = from b in db.StationEvaluationBooks
             where b.StationEvaluationID.HasValue &&
                   ids.Contains(b.StationEvaluationID.Value)
             select b;

Or best option

var result = db.StationEvaluation.Where(/*condition*/)
               .SelectMany(s => s.StationEvaluationBooks);

Upvotes: 5

Corey Adler
Corey Adler

Reputation: 16137

Based on your most recent update, how about this:

var stationEvaluations = db.StationEvaluation.Where(/*condition*/)
                                             .Select(st => st.StationEvaluationID);

var result = from c in db.StationEvaluationBooks
                       where stationEvaluations.Contains(c.StationEvaluationID)
                       select c;

Upvotes: 2

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