Cannot insert the value NULL into column EF Code First

Question

I have a project that uses Entity Framework Code First and I'm running in the insert error "Cannot insert the value NULL into column". Here's my code

[Table("Foo")]
public class Foo
{
    [Key]
    public int FooId { get; set; }
    public string Name { get; set; }

    public virtual List<Bar> Bar { get; set; }
}

[Table("Bar")]
public class Bar
{
    [Key, Column(Order = 0), ForeignKey("Foo")]
    public int FooId{ get; set; }

    [Key, Column(Order = 1), DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int BarId { get; set; }
    public DateTime Date { get; set; }

    public virtual Foo Foo { get; set; }
}

And a Insert Method that uses AutoMapper to map a Dto into Foo entity.

    public bool Insert(Foo obj)
    {
        Foo newFoo = this.MapFooEntity(obj);
        this._context.Foo.Add(newFoo);
        this._context.SaveChanges();
        return true;
    }

The Foo Object AutoMapper generates don't have any problems, it generate Foo with FooId = 0 and any child (Bar) with BarId = 0. In my view the EF should have see that BarId = 0 and attach the next indentity ID to it, but I'm getting that error. What are your thoughts guys ?

Answer 1

Please try the following modification to your code:

In class Bar, put [ForeignKey("FooId")] before

public virtual Foo Foo { get; set; }

and put [InverseProperty("Foo")] before

public virtual List<Bar> Bar { get; set; }

in class Foo.