DbSet在EntityFramework CodeFirst中的过滤

Question

这是ApplicationUser：

public class ApplicationUser : IdentityUser<long>
{
    public string Firstname { get; set; }
    public string Lastname { get; set; }
    public UserTypes Type { get; set; }
    public string FullName { get { return $"{Firstname ?? ""} {Lastname ?? ""}".Trim(); } }
}

我们有3种不同的UserTypes (提供者、支持者、NormalUser (即ApplicationUser))

public class Provider : ApplicationUser{
   // Provider related virtual Icollections
}

public class Supporter : ApplicationUser{
   // Supporter related virtual Icollections
}

现在，在ApplicationDbContext中，我希望在ApplicationUser旁边有这些DbSet：

public virtual DbSet<Provider> Providers{get;set;}
public virtual DbSet<Supporter> Supporters{get;set;}

哪个DbSet<Provider>应该返回其UserTypes等于2的ApplicationUsers (例如)

Answer 1

     public class ApplicationDbContext : IdentityDbContext<ApplicationUser, IdentityRole<long>, long>
        {

            public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
                : base(options)
            {
            }
            public ApplicationDbContext()
                : base()
            {
            }

            public virtual IEnumerable<Provider> Providers
            {
                get
                {
                    return (IEnumerable<Provider>)Users.Where(z => z.Type == UserTypes.Provider).AsEnumerable();
                }
            }
         }