The member with identity ' ' does not exist in the metadata collection.\r\nParameter name: identity

Question

I simplified the code a little while trying to debug:

[HttpPost]
    public ActionResult Register(User model)
    {
        DateTime bla = new DateTime(2012, 12, 12);
        try
        {
            User user = new User
            {
                gid = 1,
                cid = 1,
                firstName = model.firstName,
                lastName = model.lastName,
                email = model.email,
                username = model.username,
                password = model.password,
                creationDate = bla,
                active = 1
            };
            myContext.Users.AddObject(user);
            myContext.SaveChanges();

        }
        catch (Exception ex)
        {
            throw ex;
        }

        return View();               
    }

The values are transmited accordingly. Users table:

[id] [int] IDENTITY(1,1) NOT NULL,
[cid] [int] NULL,
[gid] [int] NULL,
[firstName] [nvarchar](100) NOT NULL,
[lastName] [nvarchar](100) NOT NULL,
[email] [nvarchar](max) NOT NULL,
[username] [nvarchar](100) NOT NULL,
[password] [nvarchar](100) NOT NULL,
[creationDate] [datetime] NOT NULL,
[active] [int] NOT NULL,

CONSTRAINT [PK_Users_3213E83F0AD2A005] PRIMARY KEY CLUSTERED

I deleted all the foreign keys to be sure that nothing affects it. I am qute certain that at a previous moment it was working, but now I can not figure where the issue is. It crashes while performing the savechanges:

{"An error occurred while updating the entries. See the inner exception for details."}
{"The member with identity '' does not exist in the metadata collection.\r\nParameter name: identity"}

Answer 1

I had the same error being thrown when I try to insert using EF, the error was

The member with identity 'Id' does not exist in the metadata collection.\r\nParameter name: identity

It wasn't obvious at first but the exception message was very concise because my database knows the column Id int but the property created for the object on my code was int ID so coming back to named mapping, Id is not mapped to ID.

So when an object with property ID is sent to database that only know Id you will get the above error.

I hope this helps, thanks