Question

I’m trying to populate class A (sorry for bad naming), with data from EF using Linq.

Got these classes:

public class A
{
    public string SomeA { get; set; }
    public B B { get; set; }
    public List<C> C { get; set; }
}

public class B
{
    public string SomeB { get; set; }
    public string SomeB2 { get; set; }
}

public class C
{
    public string SomeC { get; set; }
    public string SomeC2 { get; set; }
}

My SQL query to get all info needed looks like:

SELECT * FROM A
    JOIN B ON A.X = B.X
    LEFT JOIN C ON C.X = B.X

How would the linq query look like to populate A?

List<A> things = ......

Thanks in advance

/Lasse

Answer 1

It’s easier than you might expect:

List<A> things = (
    from thing in db.As
    where thing.B.C != null
    select thing)
    .ToList();

Note: for this to work, your EF model must understand there is a FK relationship between B and C. When that’s the case (which will normally be when that FK is in the database and you generated your model directly from the database definition), EF will generate the C property on B (and vice versa).