EF Lazy load proxy interceptor

Question

I'm looking for a way to intercept Entity Framework's lazy load proxy implementation, or otherwise control what is returned when accessing a Navigation property that may have no value in the database.

An example of what I'm looking for is this Contact class with mailing address, business phone, etc. that may or may not have a contact person.

public partial class Contact
{
        private Nullable<System.Guid> _personId;
        public Nullable<System.Guid> PersonId 
        { 
            get { return _personId; } 
            set { SetProperty(ref _personId, value); } 
        }

        public virtual Person Person{ get; set; }

    // mailing address, other properties...
}

public partial class Person
{
        private string _firstName;
        public string FirstName 
        { 
            get { return _firstName; } 
            set { SetProperty(ref _firstName, value); } 
        }

        private string _lastName;
        public string LastName 
        { 
            get { return _lastName;} 
            set { SetProperty(ref _lastName;value); } 
        }
}

It is very useful in ASP.net Razor pages, WPF or ad-hoc reporting tools, to be able to use expressions like:

Contact c = repo.GetContact(id);
Console.WriteLine("Contact Person " + c.Person.FirstName);

Which of course fails if there is no PersonId, and hence contact.Person is null.

Tools like Ideablade Devforce have a mechanism to return a "NullEntity" for Person in this case, which allows the WriteLine to succeed. Additionally, the NullEntity for Person can be configured to have a sensible value for FirstName, like "NA".

Is there some way to override the Dynamic Proxy mechanism in EF, or otherwise intercept the reference to Person from Contact to enable this scenario?

I have investigated IDbCommandInterceptor, but that does not seem to intercept virtual navigation to individual entity properties, only navigation to entity collections.

Update _____________________________________

To elaborate on my original question, I can't modify the expression by introducing null conditional operators into the them, as these expressions are incorporated into WPF, ASP.Net Razor binding expressions, and/or report data fields, created by other developers or authors. Also, there may be multiple layers of null properties to deal with, e.g. Contact.Person.Spouse.FirstName, where either Person and/or Spouse might be a "null" property. The Devforce Ideablade implementation deals with this perfectly, but is unfortunately not an option on my current project.

Answer 1

you can use a null-conditional operator from c# like this

c.Person?.FirstName

This means that when Person == null , return null or otherwise return FirstName. You would still need to handle the null value

See : https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/member-access-operators#null-conditional-operators--and-