How to extend User Identity with an IEnumerable/Collection property

Question

Similar to this question: How to extend available properties of User.Identity

When a user logs in I'd like to load the departments my user has an association with. I'm guessing that I'd add a property to the ApplicationUser class like this:

public class ApplicationUser : IdentityUser<Guid, GuidUserLogin, GuidUserRole, GuidUserClaim>
    {
        public async Task<ClaimsIdentity> GenerateUserIdentityAsync(ApplicationUserManager manager)
        {
            // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
            var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
            return userIdentity;
        }


        public IEnumerable<Department> Departments { get; set; }
    }

My question is how/where would I populate the collection, and then how would I access the property later in my controllers. From what I understand, claims would be OK for simple types - an Id for example - but can they be used with collections?

I'm assuming once I have this property loaded, I'd be able to query the collection without hitting the database each time I need this information about the user - which will be often.

Any help appreciated.

Answer 1

First of all, create the collection entity, i.e. Department. Then reference the Id of the ApplicationUser entity within that.

Assuming you use entity framework code-first, here is an example:

public class ApplicationUser : IdentityUser<Guid, GuidUserLogin, GuidUserRole, GuidUserClaim>
    {
        public async Task<ClaimsIdentity> GenerateUserIdentityAsync(ApplicationUserManager manager)
        {
            // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
            var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
            return userIdentity;
        }

        public ApplicationUser()
        {
           Departments = new Collection<Department>();
        }

        public ICollection<Department> Departments { get; set; }
    }



public class Department
{

    public string UserId { get; set; }

    public int DepartmentId { get; set; }

    public ApplicationUser User { get; set; }

    protected Department()
    {

    }

}