将父级保存到EF时如何排除子级对象？

Question

I have a nullable foreign key from my parent to my child:

public class Company
{
    public int? AddressID {get;set;}
    public Address Address {get;set;}
}

public class Address
{
    public string StreetAddress {get;set;} //not nullable in DB
}

When I try and save to the Database EF tries to save the Address object despite it being null:

var company = new Company{AddressID = null } //other stuff is populated that matters

try
{
    _context.Entry(company).State = EntityState.Added;
    _context.SaveChanges();
}
catch (Exception exception)
{
    //Throws Validation error because StreetAddress is not nullable
}

I tried these

{
    _context.Entry(company).State = EntityState.Detached;
    _context.Company.Add(company);
}

{
    _context.Companies.Add(company);
}

Both of them still require a street address be populated.

How can I ignore the nullable children when saving?

Answer 1

I have a hunch the child foreign key is non-nullable. Try setting the property to virtual:

public virtual Address Address { get; set; }