实体框架代码优先不会将身份设置为是

Question

I have classes for a Code First implementation and I am trying to get it to create the table so that the Id Field is set to Identity = yes. Not matter what I do though it always seems to be set to no.

I've tried adding the .HasKey and the HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity) on the Id property as follows:

 public class ApplicationDbContext : IdentityDbContext<User, Role, Guid, UserLogin, UserRole, UserClaim>
 {
      protected override void OnModelCreating(DbModelBuilder modelBuilder)
      {
          modelBuilder.HasDefaultSchema("dbo");

                      modelBuilder.Entity<User>().Map(c =>
        {
            c.ToTable("User");
            c.Property(p => p.Id).HasColumnName("UserId");                
            c.Properties(p => new
            {
                p.AccessFailedCount,
                p.Email,
                p.EmailConfirmed,
                p.PasswordHash,
                p.PhoneNumber,
                p.PhoneNumberConfirmed,
                p.TwoFactorEnabled,
                p.SecurityStamp,
                p.LockoutEnabled,
                p.LockoutEndDateUtc,
                p.UserName,
                p.FirstName,
                p.MiddleName,
                p.LastName,
                p.IsActive,
                p.LastLogin,
                p.CreatedBy,
                p.CreatedOn,
                p.LastModifiedBy,
                p.LastModifiedOn
            });
        }).HasKey(c => c.Id);
        modelBuilder.Entity<User>().HasMany(c => c.Logins).WithOptional().HasForeignKey(c => c.UserId);
        modelBuilder.Entity<User>().HasMany(c => c.Claims).WithOptional().HasForeignKey(c => c.UserId);
        modelBuilder.Entity<User>().HasMany(c => c.Roles).WithRequired().HasForeignKey(c => c.UserId);
        modelBuilder.Entity<User>().Property(p => p.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        modelBuilder.Entity<User>().HasKey(p => p.Id);

I've also set the Attribute on the Id Property in the Class to be Identity

    public class User : IdentityUser<Guid, UserLogin, UserRole, UserClaim>, IEntity
    {
    public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<User, Guid> manager, string authenticationType)
    {
        // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
        var userIdentity = await manager.CreateIdentityAsync(this, authenticationType);
        // Add custom user claims here
        return userIdentity;
    }
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public override Guid Id { get; set; }
    [MaxLength(256)]
    public string FirstName { get; set; }
    [MaxLength(256)]
    public string MiddleName { get; set; }
    [MaxLength(256)]
    public string LastName { get; set; }
    public bool IsActive { get; set; }
    public DateTime? LastLogin { get; set; }
    public Guid? CreatedBy { get; set; }
    public DateTime? CreatedOn { get; set; }
    public Guid? LastModifiedBy { get; set; }
    public DateTime? LastModifiedOn { get; set; }         
}
}

The Up() method in the actual Migration comes out as follows:

CreateTable(
            "dbo.User",
            c => new
                {
                    **UserId = c.Guid(nullable: false, identity: true),**
                    FirstName = c.String(maxLength: 256),
                    MiddleName = c.String(maxLength: 256),
                    LastName = c.String(maxLength: 256),
                    IsActive = c.Boolean(nullable: false),
                    LastLogin = c.DateTime(),
                    CreatedBy = c.Guid(),
                    CreatedOn = c.DateTime(),
                    LastModifiedBy = c.Guid(),
                    LastModifiedOn = c.DateTime(),
                    Email = c.String(),
                    EmailConfirmed = c.Boolean(nullable: false),
                    PasswordHash = c.String(),
                    SecurityStamp = c.String(),
                    PhoneNumber = c.String(),
                    PhoneNumberConfirmed = c.Boolean(nullable: false),
                    TwoFactorEnabled = c.Boolean(nullable: false),
                    LockoutEndDateUtc = c.DateTime(),
                    LockoutEnabled = c.Boolean(nullable: false),
                    AccessFailedCount = c.Int(nullable: false),
                    UserName = c.String(),
                })
            .PrimaryKey(t => t.UserId);

As you can see though, when the script is ran the Identity is set to No.

Answer 1

IDENTITY is only for INT or BIGINT types, not GUID. See https://msdn.microsoft.com/en-us/library/ms186775.aspx . Related: Uniqueidentifier vs. IDENTITY vs. Material Code --which is the best choice for primary key? .