LINQ /代码优先：如何从父对象中删除子对象的引用？

Question

I have 'UserProfile' and 'Executive' objects on a 1:1 relationship using Repository pattern. UserProfiles are required/part of the system, and executives are based on UserProfiles.

Here's my UserProfile:(pertinent part)

public int? ExecutiveId { get; set; }
[ForeignKey("ExecutiveId")]
public virtual Executive Executive { get; set; }

Here's my Executive: (pertinent part)

public int UserProfileId { get; set; }
[ForeignKey("UserProfileId")]
public virtual UserProfile UserProfile { get; set; }

Here's my FluentApi:(since the executive is optional and requires a UserProfile)

modelBuilder.Entity<Executive>()
            .HasRequired(x => x.UserProfile)
            .WithOptional(s => s.Executive)
            .WillCascadeOnDelete(false); <-- I've tried 'true' here as well

Now when I try deleting it, and look in SQL Mgr, I see the UserProfile for a particular executive I've deleted is still an integer and not NULL as I expect... Here's my code to delete:

 var executive = _executiveRepository.GetExecutiveById(id);
        // remove pic/content
        _contentRepository.DeleteContent(executive.ProfilePictureContent.ContentGuid);
        // remove mappings
        _executiveSectionMappingRepository.DeleteExecutiveSectionMappingRange(executive.ExecutiveSectionMappings);
        // remove executive
        _executiveRepository.DeleteExecutive(id);
        // remove reference from User also as EF isn't doing this the way it's setup now.
        var u = _userRepository
            .GetUserProfiles()
            .FirstOrDefault(x => x.ExecutiveId == executive.UserProfileId);
        if (u != null)
        {
            u.ExecutiveId = null;<-- these don't work !!
            u.Executive = null;  <-- not working
        }
        // save
        _contentRepository.Save();
        _executiveSectionMappingRepository.Save();
        _executiveRepository.Save();
        _userRepository.Save();

what am I missing?

Answer 1

I've not work with Code first, but it looks like your saving your Repositories, but not setting that entity to be modified.

Meaning you're updating the userProfile's object in memory, but not setting your repo to use that object. {unless i'm mistaken with Code First}, but it seems you need to do something along the lines of:

_userRepository.UpdateExistingUser(u);

Then call _userRepository.Save();