Entity Framework database-first + uniqueidentity result no new guid id

Question

I cannot generate a new guid id for my primary key. Getting same error every time when I try to create an another user as it wont generate a new guid id.

Violation of PRIMARY KEY constraint 'PK_User'. Cannot insert duplicate key in object 'dbo.User'. The duplicate key value is (00000000-0000-0000-0000-000000000000). The statement has been terminated.

Code:

public partial class User
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public System.Guid Id { get; set; }
    public string UserName { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
}

My UserController code

[HttpGet]
public ActionResult Create() {
    return View();
}

[HttpPost]
public ActionResult Create(User user) {
        if (ModelState.IsValid) {
            db.Users.Add(user);
            db.SaveChanges();

            return RedirectToAction("Index");
        }

        return View(user);
}

How do I automatically generate new guids?

Answer 1

Your c# code is not generating any GUID because you are instructing it to do so. Your model says that the value of Id is generated by database (DatabaseGenerated(DatabaseGeneratedOption.Identity)) The issue is in your table definition in the database. If you are using SQL server, using SQL server management studio, review your table's definition and make sure that ID is actually defined as 'Identity'

Answer 2

you can do in constructor of class like this

public User()
{
  this.Id= Guid.NewGuid();
}