ASP .NET One-to-One Relationship CRUD

Question

There's a problem with Edit action autogenerated with controller on the basis of a code-first class UserProfile .

public class UserProfile : ApplicationUser
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public DateTime BirthDate { get; set; }
        public string ProfilePhoto { get; set; }
        public string Interests { get; set; }
        public string AboutMe { get; set; }

        public Address Address { get; set; }
        public List<Post> Posts { get; set; }
        public List<Friends> Friends { get; set; }
        public List<Messages> Messages { get; set; }
        public List<UsersGallery> UsersGallery { get; set; }
    }

UserProfile is in one-to-one relationship with class Address .

public class Address
    {
        [Key]
        public string AddressId { get; set; }

        public string City { get; set; }
        public string Street { get; set; }
        public string HouseOrFlatNumber { get; set; }
        public string PostalCode { get; set; }
        public string Country { get; set; }

        public string UserProfileForeignKey { get; set; }
        public UserProfile UserProfile { get; set; }
    }

The relationship is described in FluentApi as follows:

protected override void OnModelCreating(ModelBuilder builder)
        {
            base.OnModelCreating(builder);

            builder.Entity<UserProfile>()
            .HasOne(p => p.Address)
            .WithOne(i => i.UserProfile)
            .HasForeignKey<Address>(b => b.UserProfileForeignKey);
        }

The UserProfile and Address entities are created in Register action

public async Task<IActionResult> Register(RegisterViewModel model, string returnUrl = null)
        {
            ViewData["ReturnUrl"] = returnUrl;
            if (ModelState.IsValid)
            {
                var user = new UserProfile { UserName = model.FirstName, Email = model.Email, FirstName = model.FirstName, LastName = model.LastName, Address = new Address() };
                var result = await _userManager.CreateAsync(user, model.Password);
                if (result.Succeeded)
                {
                    _logger.LogInformation("User created a new account with password.");

                    var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
                    var callbackUrl = Url.EmailConfirmationLink(user.Id, code, Request.Scheme);
                    await _emailSender.SendEmailConfirmationAsync(model.Email, callbackUrl);

                    await _signInManager.SignInAsync(user, isPersistent: false);
                    _logger.LogInformation("User created a new account with password.");
                    return RedirectToLocal(returnUrl);
                }
                AddErrors(result);
            }

            // If we got this far, something failed, redisplay form
            return View(model);
        }

At this point I have the appropriate entries in the database tables related by the UserProfileForeignKey. - the UserProfile table the UserProfile table - the Address table the Address table

And here appears a problem. According to the sql error message, the autogenerated CRUD action Edit instead of altering the entry in Address table tries to add a new entry with the same UserProfileForeignKey.

Do I understand it correctly? Why is that so and what can be done to make the Edit action work as it should?

[HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(string id, [Bind("FirstName,LastName,BirthDate,ProfilePhoto,Interests,AboutMe,Address,Id,UserName,NormalizedUserName,Email,NormalizedEmail,EmailConfirmed,PasswordHash,SecurityStamp,ConcurrencyStamp,PhoneNumber,PhoneNumberConfirmed,TwoFactorEnabled,LockoutEnd,LockoutEnabled,AccessFailedCount")] UserProfile userProfile)
        {
            if (id != userProfile.Id)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(userProfile);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!UserProfileExists(userProfile.Id))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }
            return View(userProfile);
        }

Here is the sql error message:

An unhandled exception occurred while processing the request.

SqlException: Cannot insert duplicate key row in object 'dbo.Address' with unique index 'IX_Address_UserProfileForeignKey'.

The duplicate key value is (9872561e-dad4-4169-9faf-154c7dcd925f). The statement has been terminated.

System.Data.SqlClient.SqlCommand+<>c.b__108_0(Task result) DbUpdateException: An error occurred while updating the entries. See the inner exception for details.

Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch+d__32.MoveNext()

It says the ForeignKey 9872561e-dad4-4169-9faf-154c7dcd925f is tried to be duplicated but why if it is an update not an insert?

Answer 1

This is because you UserProfile entity is detached (entity framework is not tracking it), so it sets entity.State == Added here. To attach your entity please see How to Update Existing Disconnected Entity

Edit 27/01/2018 I tried to replicate your scenario and have created a project in GitHub https://github.com/updateaman/EF6-Test

After setting/passing the UserProfileForeignKey property inside Address object, I was able to get rid of this error