MVC Identity - The INSERT statement conflicted with the FOREIGN KEY constraint

Question

I know this question has already been discussed a couple of times but this one relates to the built in Identity model.

I've created a custom model named "Company". When registering new users I want to select also the company name.

I've added the required data into the RegisterViewModel and the Views and the forms displays as it should. I already seeded 2 companies in the Company table so the value should not be null.

public class RegisterViewModel
{        
   ... Removed some irrelevant code ...

    [Required(ErrorMessage = "You must select a company name.")]
    [Display(Name = "Company")]
    public int CompanyID { get; set; }
    public virtual Company ApplicationUser_Company { get; set; }

The problem arises when I want to insert a new user with the following error:

The INSERT statement conflicted with the FOREIGN KEY constraint "FK_dbo.AspNetUsers_dbo.Companies_CompanyID". The conflict occurred in database "aspnet-ProjectMed-20160327120257", table "dbo.Companies", column 'CompanyID'.
The statement has been terminated. 

Checking the account controller I cannot see any problem:

    // GET: /Account/Register
    [AllowAnonymous]
    public ActionResult Register()
    {
        ViewBag.CompanyID = new SelectList(db.Companies, "CompanyID", "Company_Name");
        return View();
    }

    //
    // POST: /Account/Register
    [HttpPost]
    [AllowAnonymous]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Register(RegisterViewModel model)
    {
        if (ModelState.IsValid)
        {
            var user = new ApplicationUser { UserName = model.Email, Email = model.Email, ApplicationUser_FirstName = model.ApplicationUser_FirstName, ApplicationUser_LastName = model.ApplicationUser_LastName, ApplicationUser_Company = model.ApplicationUser_Company };

                var result = await UserManager.CreateAsync(user, model.Password); <<<---- This is where the error occurs <<<---
                if (result.Succeeded)
                {
                    await SignInManager.SignInAsync(user, isPersistent: false, rememberBrowser: false);

                    return RedirectToAction("Index", "Home");
                }
                AddErrors(result);

        }

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

I am also copying the SQL tables:

AspNetUsers table:

CREATE TABLE [dbo].[AspNetUsers] (
    [Id]                        NVARCHAR (128) NOT NULL,
    [ApplicationUser_FirstName] NVARCHAR (50)  NOT NULL,
    [ApplicationUser_LastName]  NVARCHAR (50)  NOT NULL,
    [CompanyID]                 INT            NOT NULL,
    [Email]                     NVARCHAR (256) NULL,
    [EmailConfirmed]            BIT            NOT NULL,
    [PasswordHash]              NVARCHAR (MAX) NULL,
    [SecurityStamp]             NVARCHAR (MAX) NULL,
    [PhoneNumber]               NVARCHAR (MAX) NULL,
    [PhoneNumberConfirmed]      BIT            NOT NULL,
    [TwoFactorEnabled]          BIT            NOT NULL,
    [LockoutEndDateUtc]         DATETIME       NULL,
    [LockoutEnabled]            BIT            NOT NULL,
    [AccessFailedCount]         INT            NOT NULL,
    [UserName]                  NVARCHAR (256) NOT NULL,
    CONSTRAINT [PK_dbo.AspNetUsers] PRIMARY KEY CLUSTERED ([Id] ASC),
    CONSTRAINT [FK_dbo.AspNetUsers_dbo.Companies_CompanyID] FOREIGN KEY ([CompanyID]) REFERENCES [dbo].[Companies] ([CompanyID]) ON DELETE CASCADE
);

GO
CREATE NONCLUSTERED INDEX [IX_CompanyID]
    ON [dbo].[AspNetUsers]([CompanyID] ASC);

GO
CREATE UNIQUE NONCLUSTERED INDEX [UserNameIndex]
    ON [dbo].[AspNetUsers]([UserName] ASC);

Companies table:

CREATE TABLE [dbo].[Companies] (
    [CompanyID]          INT            IDENTITY (1, 1) NOT NULL,
    [Company_Name]       NVARCHAR (50)  NOT NULL,
    [Company_Code]       NVARCHAR (9)   NOT NULL,
    [Company_Address1]   NVARCHAR (100) NOT NULL,
    [Company_Address2]   NVARCHAR (100) NULL,
    [Company_PostalCode] NVARCHAR (15)  NOT NULL,
    [Company_City]       NVARCHAR (50)  NOT NULL,
    [CountryID]          INT            NOT NULL,
    [Company_CLOG]       BIT            NOT NULL,
    [Company_SubAgent]   BIT            NOT NULL,
    CONSTRAINT [PK_dbo.Companies] PRIMARY KEY CLUSTERED ([CompanyID] ASC),
    CONSTRAINT [FK_dbo.Companies_dbo.Countries_CountryID] FOREIGN KEY ([CountryID]) REFERENCES [dbo].[Countries] ([CountryID]) ON DELETE CASCADE
);


GO
CREATE UNIQUE NONCLUSTERED INDEX [IX_Company_Code]
    ON [dbo].[Companies]([Company_Code] ASC);


GO
CREATE NONCLUSTERED INDEX [IX_CountryID]
    ON [dbo].[Companies]([CountryID] ASC);

Any ideas and what's wrong here?

Answer 1

It seems I've found the error thanks to your last suggestion! I was trying to set the value of the foreign key instead if the ID...

The code that worked for me:

[HttpPost]
public async Task<ActionResult> Register(RegisterViewModel model)
{
  // verify the models' valid
  if (ModelState.IsValid)
  {
      var user = new ApplicationUser {
        /* ... */,
        CompanyID = model.CompanyID // entity we retrieved
      };

      //
      // SignInManager yatta yata
      //
  }
  return View(model); // Uh-oh fallback.
}