Creating a 1:1 relationship using EF CodeFirst - entity-framework

Question

I am battling with EF code first and trying to map a 1:1 relationship with no joy.
Basically a user can have a userdetail.
I am setting primary keys on both tables.On my UserDetail table has field UserId I am trying to use as the FK.
public class User:BaseModel
{
public virtual UserDetail UserDetail { get; set; }
public string UserName { get; set; }
}
public class UserDetail:BaseModel
{
public virtual User User { get; set; }
[ForeignKey("User")]
public int UserId { get; set; }
public string UserDetailName { get; set; }
}
public class BaseModel{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
}
When I try using the add-migration command I get this error
UserDetail_User_Source: : Multiplicity is not valid in Role 'UserDetail_User_Source' in relationship 'UserDetail_User'. Because the Dependent Role properties are not the key properties, the upper bound of the multiplicity of the Dependent Role must be '*'.
What do I need to do to get this working? Surely this shouldnt be that difficult?
Update below based on comment from #steve-green
I configured the fluentapi like steve suggested
modelBuilder.Entity<User>()
.HasRequired(t => t.UserDetail)
.WithRequiredPrincipal(t => t.User);
however the generated migration step looks wrong to me
CreateTable(
"dbo.Users",
c => new
{
UserId = c.Int(nullable: false, identity: true),
UserName = c.String(),
})
.PrimaryKey(t => t.UserId);
CreateTable(
"dbo.UserDetails",
c => new
{
UserDetailId = c.Int(nullable: false, identity: true),
UserId = c.Int(nullable: false),
UserDetailName = c.String(),
})
.PrimaryKey(t => t.UserDetailId)
.ForeignKey("dbo.Users", t => t.UserDetailId)
.Index(t => t.UserDetailId);
The FK is configured as UserDetailId shouldnt it be UserId?
Slightly modified model
public class UserDetail
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int UserDetailId { get; set; }
public virtual User User { get; set; }
public int UserId { get; set; }
public string UserDetailName { get; set; }
}

Answer 1

Get rid of the attribute
[ForeignKey("User")
in UserDetail. Also, i would add
int UserDetailId
to User
That should then work.

Answer 2

If you are going to use a base table, then you can't do it with annotations because (as you mention) the key on the required dependent needs to be a foreign key. You will need fluent api code:
modelBuilder.Entity<User>()
.HasRequired(t => t.UserDetail)
.WithRequiredPrincipal(t => t.User);
https://msdn.microsoft.com/en-us/data/jj591620.aspx#RequiredToRequired