Assigning UserId to Foreign Key = null

Question

I'm using Entity Framework 5 and MVC 4, with .NET 4.5 using Code First migrations. I have foreign keys between two entities in a 1 to zero-or-1 relationship. When I try to create the record for Jogger everything blows up. I get error messages that are either: - Foreign Key is a null reference - dbo.Jogger does not exist - Unhandled exception ... no metadata. When I run the EF Viewer the navigation relationships are perfect. No Fluent API code is used at the moment. User Class ``` [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int UserId { get; set; } public string UserName { get; set; } // Other properties public int? JoggerId { get; set; } public virtual Jogger Jogger { get; set; } ``` Jogger Class ``` [ForeignKey("UserId")] public int JoggerId { get; set; } public virtual UserProfile UserId { get; set; } ``` When the JoggerController is generated it produces this code for the Get and Post Methods: ``` // GET: /Jogger/Create public ActionResult Create() {…

Accepted Answer

After much trial and error I found a way that works to assign the Foreign Key a value.

Firstly, my relationships were setup incorrectly: UserProfile Class did not need the public int? GolferId to represent a navigation property. Final classes looked as follows:

UserProfile

```
  [Key]
  [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
  public int UserId { get; set; }
  public string UserName { get; set; }

// Navigation properties
  public virtual Jogger Jogger { get; set; }
```

Jogger Class

```
[Key] 
[ForeignKey("UserId")]
public int JoggerId { get; set; }

public string Pronation {get; set;}

public virtual UserProfile UserId { get; set; }
```

This setup the correct relationship without needing any Fluent API code.

To assign the ForeignKey value was a little trickier and I'm sure there are MUCH better ways of doing it than this.

- Instead of the other scaffolding method of defining (id = 0), I used a FormCollection. You can also use the [Bind(Include = "field1, field2, field3")] to ensure that the correct fields are being posted.

- There's a long way of getting to the logged-in User's UserId which takes advantage of User.Identity.Name

The FormCollection allows me to reference and save the other fields e.g. Pronation

```
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(FormCollection values)
{

var jogger = new Jogger();
    TryUpdateModel(jogger);

var context = new TestContext();
    var userqq = User.Identity.Name;
    var user = context.UserProfiles.SingleOrDefault(u => u.UserName == userqq);

if (ModelState.IsValid)
    {

jogger.JoggerId = user.UserId;
            jogger.Pronation = values["Pronation"];

db.Joggers.Add(jogger);
            db.SaveChanges();
           return View();

}
        ViewBag.JoggerId = new SelectList(db.UserProfiles, "UserId", "UserName", jogger.JoggerId);
        return View(jogger);

}
```

This wasn't pretty at all but it does work. Thanks to @Moeri for pointing me in the right direction.

Assigning UserId to Foreign Key = null

Solution

Problem