Question

With lazy loading configured, I run into an issue regarding object comparison. My overriden Equals-method within each domain entity class contains the following line:

if (obj == null || !obj.GetType().Equals(GetType()))

Obviously, The type comparison will fail as obj is a proxy instance. I’ve already seen some NHibernate-snippets which unproxy an object and return the real instance. But as I enforce a domain driven design, I do not want any ORM-specific code within my domain layer.
I also cannot unproxy the instance on caller side [e.g. foo.Equals(Unproxy(bar))] as the caller is my application layer which also doesn’t contain any ORM-specific code (all NHibernate dependencies are injected by Windsor).

Long story short: is there any generic code to get the real instance?

Answer 1

The way to solve that is to do a cast:

public class Person
{
    public int Id { get; set; }

    public override bool Equals(object obj)
    {
        var person = obj as Person;

        if (person == null)
        {
            return false;
        }

        return person.Id == this.Id;
    }
}

The cast works because the proxy inherits from your class (e.g. PersonProxy : Person)

The null check is unnecessary as the as cast will just return null if obj is either null or not an object that can be cast as a person.