Using Linq to get records that have specific foreign key

Question

I'm trying get all records from a table that have a specific foreign key but I'm struggling to get linq to return anything useful.

Post Model

public class Post
{
    //... irrelevant properties
    [ForeignKey("Category")]
    public int CategoryId;
    public virtual Category Category { get; set; }
}

my dbo.Posts table

enter image description here

What I've tried

I've tried several variations of the following:

//id = 7

using (UnitOfWork uwork = new UnitOfWork())
{
    var post = uwork.PostRepository.GetAll().Where(c => c.CategoryId == id);

}

This only returns "Non-Public members", which doesn't contain anything useful.

enter image description here

Question

How could I modify my linq query to return all posts that have a specific Foreign Key id?

updates

here's my repository

What does the repository do on GetAll?

Andrei
– Andrei

2015-07-15 00:26:51 +00:00
Commented Jul 15, 2015 at 0:26 — Andrei
– Andrei, Commented Jul 15, 2015 at 0:26

Andrei · Accepted Answer · 2015-07-15 00:35:11Z

3

It seems that you are basically looking at DbQuery<T> object, which is an implementation of IQueryable<T>. Basically LINQ did not make a query yet, because no one asked it for data. So instead it collects all info about the query in an object, to execute it later when needed.

To force it to give you the actual data, simply do ToList, or iterate over posts, or anything:

var post = uwork.PostRepository.GetAll().Where(c => c.CategoryId == id).ToList();

Just make sure to do so before you expose the db context object.

answered Jul 15, 2015 at 0:35

Andrei

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3 Comments

Dan Beaulieu Over a year ago

This threw an error: The specified type member 'CategoryId' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.

Andrei Over a year ago

Well, that's now entire different story. Something is wrong with your ORM mapping. Looks like you have Category_Id in your table, and CategoryId in the object - that might be an issue. But the key thing is that linq did execute the query now

Dan Beaulieu Over a year ago

Agreed, looks like I need to update my model. thank you and I'll accept this as the answer

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Using Linq to get records that have specific foreign key

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