CODEWITHSUNDEEP
c#linqentity-framework
Mark
Mark

Reputation: 7818

Adding a linked object to another object in C# ASP.Net MVC

I have a model as follows:

public class Analyst
{
    public int AnalystId { get; set; }
    public string AnalystName { get; set; }
    public string CorpId { get; set; }
    public string TeamLeader { get; set; }
    public string TLCorpId { get; set; }
    public IList<Objective> Objectives { get; set; }
    public IList<ObScore> ObScores { get; set; }
}

public class Objective
{
    public int ObjectiveId { get; set; }
    public int AnalystId { get; set; }
    public string Title { get; set; }
    public string Description { get; set; }
    public int Weight { get; set; }
    public Analyst Analyst { get; set; }
}

I am trying to find a specific Objective which I can do with:

Objective objective = db.Objectives.Find(id);

...however I would also like to include the Analyst associated with the objective, so I ca reference a property on the oinked Analyst object:

if (objective.Analyst.TLCorpId != tl)

But when I'm trying to add the analyst object I get an error:

Objective objective = db.Objectives.Include(x => x.Analyst).Find(id);

System.Linq.IQueryable<Objectives.Models.Objective> does not contain a definition for 'Find' and no extension method 'Find' accepting a first argument of type System.Linq.IQueryable<Objectives.Models.Objective> could be found (are you missing a using directive or an assembly reference?)

Is there any way around this please?

Upvotes: 1

Views: 155

Answers (2)

Sergey Berezovskiy
Sergey Berezovskiy

Reputation: 236248

Method Find defined on DbSet<T>. Method Include is defined on base class DbQuery<T>. And problem here is that Include returns instance of base class, i.e. DbQuery<T> which don't have method Find (lambda-based include is just syntax sugar for calling same string-based include method). And even casting will not help you here, because new instance of base class is created internally:

public DbQuery<TResult> Include(string path)
{
    return new DbQuery<TResult>(this._internalQuery.Include(path));
}

So, use SingleOrDefault to get entity by id

Objective objective = db.Objectives.Include(x => x.Analyst)
                                   .SingleOrDefault(x => x.ObjectiveId == id);

NOTE: One difference here is that Find first checks if entity already exists in context before making database query.

Upvotes: 2

Moin
Moin

Reputation: 166

You can use

Objective objective = db.Objectives.Find(id).Where(y=>y.Analyst.TLCorpId != tl).First();

Dont forget to check for nulls

Upvotes: 1

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